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THE  RELATION  OF  FATIGUE  TO 
INDUSTRIAL  ACCIDENTS 


A  DISSERTATION 

SUBMITTED  TO  THE  FACULTY   OF   THE   GRADUATE   OF   SCHOOL  ARTS 

AND  LITERATURE  IN  CANDIDACY  FOR  THE  DEGREE 

OF  DOCTOR  OF  PHILOSOPHY 

(DEPARTMENT  OF  SOCIOLOGY) 


BY 
EMORY  S.  BOGARDUS 


Reprinted  from 

THE  AMERICAN  JOURNAL  OF  SOCIOLOGY,  XVII  (1911-12) 
CHICAGO,  1912 


Composed  and  Printed  By 

The  University  of  Chicago  Press 

Chicago,  Illinois.  U.S.A. 


I.    INTRODUCTION1 

The  discussion  of  any  question  relative  to  industrial  accidents 
remains  incomplete  if  the  influences  and  possible  consequences  of 
fatigue  are  not  considered.2  The  origin  of  the  problem  of  fatigue 
in  industry  is  to  be  found  in  connection  with  the  industrial  revo- 
lution. Before  the  introduction  of  the  factory  system,  employer 
and  employee  usually  worked  side  by  side  as  companions.  The 
blacksmith  had  a  helper  or  two ;  the  farmer  had  his  "hired  hand" ; 
the  shoemaker,  an  apprentice.  Tools  were  simple;  accidents, 
rare.  The  occupations  were  usually  not  hazardous;  the  existing 
dangers,  if  any,  were  obvious.  People  generally  worked  from 
"sun  to  sun/'  but  in  a  more  or  less  leisurely  fashion. 

When  hand-driven  tools  were  supplanted  by  power-driven 
machinery,  and  the  home  gave  way  to  the  factory  as  the  unit  of, 
production,  the  long  hours  of  labor  were  carried  over.    Monoto-  \ 
nous,  speeded-up  processes  took  the  place  of  interesting  forms 
of  work  at  a  leisurely  rate.     At  about  the  same  time,  work  by 
artificial  light  was  made  possible.     Consequently,  work-hours, 
instead  of  being  shortened  to  suit  the  new  mechanical  processes, 
were  "considerably  lengthened,  and  in  the  case  of  child  labor 
particularly,  to  a  cruel  degree."3    As  late  as  1842,  for  instance, 
the  working  day  in  cotton  mills  (United  States)  was  fourteen 
hours  long.     When  domestic  industry  was  supplanted  by  the 
factory  system,  not  only  men  but  women  and  children  in  large 
numbers  were  subjected  to  the  monotonous,  speeded-up  processes  \ 
of  machine  labor  and  for  extremely  long  hours.    Herein  is  to  be 
found  the  origin  of  the  problem  of  fatigue  in  industry. 

From  such  a  beginning,  the  fatigue  problem  developed  rapidly 
under  cover  of  the  laissez-faire  philosophy  of  the  last  century. 
It  was  held  by  the  theorists  that  if  labor  conditions  became  too 

1 1  am  indebted  to  Professor  C.  R.  Henderson  for  suggesting  this  problem. 
3  A.  Imbert.     14.  Intern.  Kongr.  f.  Hyg.  u.  Demog.,  II,  634. 
3  Adams  and  Sumner,  Labor  Problems  (Macmillan,  1008),  515. 

i 


255768 


2  RELATION  OF  FATIGUE   TO  INDUSTRIAL  ACCIDENTS 

severe  in  one  factory,  the  laborers  would  leave  and  flock  to  other 
factories  where  more  favorable  conditions  existed.  But  such 
freedom  of  choice  was  not  actually  open  to  working  men  and 
women,  for  the  severe  labor  conditions  came  to  prevail  generally. 
In  this  way,  under  the  protection  of  laissez  faire,  the  fatigue 
problem  came  to  assume  amazing  proportions.  Thus  it  has 
escaped  social  vigilance  until  within  the  last  few  years,  and  today 
it  presents  almost  insuperable  difficulties.  It  has  recently  been 
said  that  among  the  many  problems  of  industrial  hygiene,  the 
most  important  has  hitherto  been  most  neglected — the  problem  of 
industrial  overstrain.  Josephine  Goldmark  designates  overfa- 
tigue  as  "the  commonest  and  most  subtle  danger  of  occupation," 
and  says  that  in  the  United  States  this  danger 

has  not  yet  been  faced  nor  even  fairly  stated ;  yet  no  one  element  of  industry 
is  more  fraught  with  peril  for  workers.  Indeed,  overfatigue  or  exhaustion 
— surmenage  as  the  French  call  it — affects  every  department  of  life,  physical 
and  economic,  mental,  moral.  It  predisposes  to  disease;  it  destroys  intelli- 
gence and  all  the  habitual  restraints;  it  cuts  down  output  and  impairs  its 
quality;  it  invites  industrial  accidents.  It  affects  not  only  workers  in  admit- 
tedly dangerous  occupations  but  all  workers — every  man,  woman,  and  child 
employed  for  excessive  working  hours.4 

The  problem  of  fatigue  in  industry  has  at  least  six  phases : 
(a)  the  relation  of  fatigue  to  industrial  accidents;  (6)  fatigue 
and  industrial  inefficiency — presumably  poorer  work  and  less 
work  is  done  in  the  last  hour  of  a  day's  labor  than  in  other  hours ; 
(c)  fatigue  and  contagious  diseases — an  overworked  laboring 
man  or  woman  is  probably  more  susceptible  to  pneumonia,  tuber- 
culosis, typhoid  fever,  than  is  a  person  whose  vital  resistance  is 
normal;  (d)  fatigue  and  nervous  diseases — the  evidence  indi- 
cates that  long  hours  of  feverish  haste  among  factory  workers 
lead  to  nervous  breakdown;  (e)  fatigue  and  future  generations 
— the  children  of  overworked  parents  are  likely  to  be  physical 
weaklings;  (/)  fatigue  and  morals  of  working  people — long 
hours  of  monotonous  labor  probably  increases  the  susceptibility 
of  the  human  organism  to  harmful  temptations. 

The  first  phase  of  the  general  fatigue  problem — with  which 

4  Josephine  Goldmark,  "The  Study  of  Fatigue,"  Survey  (1909),  XXII,  534. 


EMORY  S.   BOGARDUS  3 

this  report  is  concerned' — has  not  yet  been  formulated,  as  far  as 
the  writer  is  aware,  as  a  distinct  problem  in  itself.  Investiga- 
tions relative  to  accidents  have  had  largely  to  do  with  the  ob- 
jective causes ;  while  the  more  deep-seated  and  perhaps  the  more 
primary  causes  have  been  neglected.  In  spite  of  the  advance 
which  has  been  made  in  this  country  within  recent  years  in  the 
introduction  of  safety  appliances1  and  of  a  system  of  factory 
inspection,  an  enormous  human  sacrifice  is  annually  made  to 
production;  herein  lies  the  chief  reason  for  this  study.  A  few 
typical  facts  are  subjoined. 

Crystal  Eastman  found  that  526  lives  were  sacrificed  to  pro- 
duction in  one  year,  ending  June  30,  1907,  in  Allegheny  County, 
Pa.  With  respect  to  accidents,  her  report  says  there  has  been 
no  respite — each  year  has  turned  them  out  as  surely  as  the  mills 
ran  full  and  the  railroads  prospered.  In  Allegheny  County 
alone  the  number  would  reach  5,000  in  ten  years — enough  to 
make  a  small  city  of  cripples.5 

After  carefully  investigating  the  returns  from  the  labor 
offices  of  nine  states,6  Gilbert  L.  Campbell  finds  that  these  reports 
show  clearly  that  in  the  year  1907,  for  example,  a  total  of  at 
least  43,713  industrial  accidents  befell  working-men  in  the  states 
cited,  and  that  3,436  of  these  accidents  were  fatal.7  In  regard 
to  accidents  befalling  railway  employees,  Mr.  Campbell  bases 
an  estimate  on  the  statistics  gathered  by  the  Interstate  Commerce 
Commission  and  states  that  during  the  seven-year  period,  1902—7 
inclusive,  335,974  employees  were  injured  and  23,895  were  killed. 
Of  the  trainmen  alone  218,082  were  injured  and  14,888  killed. 

In  a  given  year  the  trainman  has  one  chance  in  127  of  death,  and  one 
in  9  of  injury.  Seven  years  in  the  train  service  offer  him  one  chance  in 
18  of  death,  and  if  his  place  is  one  of  average  danger  present  a  practical 
certainty  of  injury.8 

Industry  may  be  charged  not  only  with  extravagance  of  killing  and 

s  Crystal  Eastman,  Work  Accidents  and  the  Law  (Charities  Pub.  Com.,  1910),  12. 

6  These  nine  states  are:   Minnesota,  Iowa,  Wisconsin,  Illinois,  Michigan,  Ohio,  Pennsyl- 
vania, New  Jersey,  and  New  York. 

7  Gilbert  L.  Campbell,  Industrial  Accidents  and  Their  Compensation  (Houghton  Mifflin  Co., 
1911),  9,  10. 

•Ibid.,  15. 


4  RELATION  OF  FATIGUE  TO  INDUSTRIAL  ACCIDENTS 

maiming  yearly  thousands  of  workers,  but  it  seems  to  choose  for  its  victims 
many  persons  in  the  prime  of  manhood,  normally  with  years  of  life  before 
them,  and  with  obligations  but  partly  discharged  to  wives  and  children." 

Approximately  30,000  wage-earners  are  killed  by  accidents 
every  year  and  at  least  500,000  more  are  seriously  injured  (in 
the  United  States).10  John  B.  Andrews  says  that  industry 
"maims  more  men  than  war  ever  did."  Professor  H.  R.  Seager 
states  that  the  United  States  "shows  every  year  a  larger  propor- 
tion of  industrial  accidents  on  its  railroads  and  in  its  mines  and 
factories  than  any  other  civilized  land."11  Moreover,  the  re- 
sultant suffering  and  denial  of  opportunity  to  the  wives  and 
children  of  the  daily  increasing  numbers  of  the  prematurely  dead 
and  of  the  industrially  maimed  and  handicapped  for  life  are 
beyond  computation.  Professor  Henderson  asks:  "Who  can 
set  a  price  on  mangled  limbs,  tortures  of  men  caught  in  cog- 
wheels and  bands,  sawed  asunder  in  mills,  and  the  sorrow, 
anxiety,  and  despair  of  their  impoverished  families?"12  The 
enormous  blood-tax  which  industry  daily  levies  upon  wage- 
earners  makes  necessary  new  forms  of  careful  investigation  of 
the  causes,  one  of  which  may  be  fatigue. 

Difficulties  arise  at  the  outset  of  this  inquiry.  Fatigue  is  an 
illusive  phenomenon.  It  varies  with  different  workmen,  with 
different  kinds  of  work,  with  different  days.  It  also  appears  that 
fatigue  develops  insidiously  and  often  without  the  knowledge  of 
the  worker.  Moreover,  physiologists  and  psychologists  disagree 
as  to  the  nature  of  the  fatigue  processes. 

Another  kind  of  difficulty  is  common.  When  three  well- 
known  social  and  economic  writers  (two  Americans,  one  Euro- 
pean) were  communicated  with,  and  asked  for  the  references  on 
the  strength  of  which  each  had  published  the  definite  statement 
that  more  accidents  occur  in  the  last  hours  of  work  than  in  other 
hours,  no  one  of  them  could  cite  such  references.  One  of  the 
frank  confessions  reads :  "For  the  statement  you  quote,  I  imagine 
now  that  I  did  not  have  at  hand  the  European  .statistics,  and  did 

9  Op.  tit.,  21. 

"  J.  B.  Andrews,  "A  Clinic  for  Industrial  Diseases,"  Survey,  XXV,  269. 

"  H.  R.  Seager,  Social  Insurance  (Macmillan,  1910),  25. 

"  C.  R.  Henderson,  "Wood-Workers  and  Their  Dangers,"  World  To-Day  (1910),  XIX,  972. 


EMORY   S.   BOGARDUS  5 

not  know  where  to  find  them ;  or  I  would  have  been  more  specific 
in  referring  to  them." 

Attempts  to  collect  new  data  are  difficult.  Some  employers 
have  established  a  monopoly  of  knowledge  and  of  social  facts — 
facts  concerning  which  the  public  should  know.  One  day  in 
August,  1910,  the  writer  explained  to  the  attorney  of  a  company 
employing  hundreds  of  men  that  data  regarding  accident-hours 
were  wanted.  When  the  attorney  had  assured  himself  of  the 
bona  fide  nature  of  the  inquiry  and  that  personal  data,  such  as 
names,  would  be  held  strictly  in  confidence,  he  gave  the  writer 
access  to  accident  records  covering  a  period  of  years  and  giving 
the  exact  time  of  the  accidents.  A  tabulation  of  the  hours  when 
these  accidents  occurred  was  scarcely  begun  when  a  high  official 
of  the  company  happened  to  enter  the  attorney's  office.  Almost 
at  a  glance  he  unjustifiably  read  much  into  the  situation  and 
gruffly  said:  "This  is  irregular;  we  can't  have  it."  A  courteous 
explanation  that  the  sole  aim  was  to  secure  social  facts  elicited 
no  response  from  this  apparently  anti-social  individual  other  than 
a  curt  abbreviation  of  his  first  remark. 

An  investigation  of  the  relation  of  fatigue  to  industrial  acci- 
dents raises  difficulties  which  increase  on  every  hand.  On  one 
side  is  a  series  of  physiological  and  psychological  phenomena;  on 
the  other,  an  equally  involved  series  of  objective  and  social 
factors.  At  this  point  the  question  might  easily  have  been  raised 
as  to  whether  further  study  would  bring  definite  results.  It  was 
from  such  an  attitude  that  further  inquiry  was  made.  A  pre- 
liminary study  of  this  phase  of  the  general  problem  of  fatigue  in 
industry  raises  six  important  groups  of  questions,  which  will  be 
considered  in  as  many  sections. 

(a)  While  considerable  research  work  has  been  done  in  con- 
nection with  a  study  of  fatigue,  each  of  the  inquiries  has  treated 
the  phenomenon  more  or  less  independently  of  its  social  signifi- 
cance. Although  the  physiologists  and  especially  the  psycholo- 
gists have  contributed  extensively  to  the  study  of  fatigue,13  the 
writer  has  not  seen  a  description  of  the  manner  in  which  and 
the  extent  to  which  fatigue  is  psychically  related  to  accidents  in 

"  For  example,  the  description  of  the  investigations  of  Kraepelin  and  of  his  colaborers  in 
the  laboratory  at  Heidelberg  fill  several  large  volumes  of  the  Psychologische  Arbeiten. 


6  RELATION   OF  FATIGUE   TO   INDUSTRIAL  ACCIDENTS 

industry.  The  discussions  regarding  fatigue  generally  stop  with 
analyses  of  subjective  processes.  They  do  not  deal  with  fatigue 
as  a  social  problem  or  consider  it  in  relation  to  a  special  group 
of  social  phenomena — such  as  accidents.14  Is  there  not  a  need, 
then,  for  a  concise  description  of  what  the  physiologists  and  also 
the  psychologists  have  discovered  that  may  be  used  in  a  study 
of  fatigue  as  a  cause  of  accidents  ?  The  question  that  is  raised 
here  calls  for  the  formulation  of  a  law  of  the  development  of 
the  fatigue  processes  which  accompany  continued  work,  in  so 
far  as  they  may  be  related  to  accidents. 

(&)  In  the  next  place,  how  does  modern  industrial  labor  affect 
the  normal  development  of  fatigue — in  what  ways  is  the  devel- 
opment of  the  fatigue  process  hastened  in  the  case  of  present- 
day  working  people,  and  why;  and  what  are  the  observable 
circumstances  under  which  these  processes  result  in  accidents?  (c) 
Can  the  subjective  fatigue  processes  be  measured  by  means  of 
controlled  experiments  in  terms  comparable  to  the  observable 
conditions  preceding  accidents,  and  thus  be  causally  related  to 
accidents  ? 

(d)  The  fourth  question  is:  What  are  the  objective  corre- 
lates of  fatigue  in  terms  of  actual  accidents,  or  to  what  extent 
do  statistics  of  the  hours  when  accidents  occur  isolate  fatigue 
from  the  other  and  more  evident  causes?  (e)  Has  over  fatigue 
attracted  attention  to  itself  to  the  extent  that  men  of  the  busi- 
ness and  legal  world  have  pronounced  it  a  cause  of  accidents? 
Specifically,  to  what  extent  do  investigations  of  the  causes  of 
railway  accidents,  for  example,  by  the  Interstate  Commerce  Com- 
mission, isolate  fatigue  as  a  cause  of  accidents;  and  have  the 
courts  indicted  fatigue  as  a  cause  of  accidents  ? 

(/)  In  the  last  place,  should  not  all  the  facts  relative  to  this 
problem  be  brought  together  in  a  unified  whole?  The  facts  de- 
rived (i)  from  a  study  of  the  normal  development  of  fatigue, 
(2)  from  a  study  of  pathological  fatigue  under  modern  indus- 
trial conditions,  (3)  from  an  experimental  study  of  fatigue  under 

14  The  Brief  in  Defense  of  the  Ten-Hour  Law  for  Women  in  Illinois  (1909),  by  Louis  D. 
Brandeis,  assisted  by  Josephine  Goldmark,  contains  an  excellent  compilation  of  opinions  from 
European  and  American  sources  regarding  different  social  phases  of  the  fatigue  problem.  The 
brief  has  served  as  a  valuable  reference  work  in  the  preparation  of  portions  of  sections  II,  III, 
and  V  of  this  study. 


EMORY  S.   BOGARDUS  7 

controlled  conditions,  (4)  from  a  statistical  inquiry  into  accident- 
hours,  and  (5)  from  a  compilation  of  legal  opinion  relating  to 
the  problem  in  hand; — will  be  summarized  and  presented  in  de- 
fense of  the  proposition  that  fatigue  is  a  cause  of  industrial  acci- 
dents. To  the  extent  that  the  facts  show  that  fatigue  is  a  causal 
factor  of  work-accidents,  a  modified  method  of  combating  their 
prevalence  will  be  necessary.  One  general  suggestion  in  this  con- 
nection will  be  made.  In  the  next  section  a  description  of  the 
development  of  the  fatigue  processes  which  may  lead  up  to  and 
culminate  in  industrial  accidents  will  be  undertaken. 

II.    RELATED  FATIGUE  PROCESSES1 

Mosso  was  among  the  first  to  point  out  in  a  scientific  way 
the  fatal  struggle  between  the  machine-operative,  subject  to  the 
laws  of  fatigue  and  exhaustion,  and  the  machine  itself,  powerful 
and  indefatigable.2  He  designates  fatigue  as  a  chemical  process. 
The  earliest  experiments  relative  to  fatigue  were  of  a  chemical 
nature. 

Normal  muscle-tissue  has  the  power  of  changing  the  sugar 
brought  to  it  by  the  blood  into  glycogen  (C6H2O6— H2O= 
C6H10O5).  The  muscle  stores  away  the  glycogen  thus  formed 
and  it  becomes  a  constant  constituent  of  a  normal  muscle.  The 
glycogen  which  the  muscle  has  stored  away  while  resting  is  con- 
sumed during  activity.  If  the  activity  is  sufficiently  prolonged, 
the  glycogen  disappears  entirely  and  exhaustion  of  the  muscle  is 
likely  to  result.  It  has  been  shown  by  verified  experiments  that  if 
most  of  the  carbohydrate  (or  glycogen)  be  removed  from  the 
body  of  an  animal,  the  organism  gives  the  'Symptoms  of  "pro- 
nounced fatigue."3  The  same  result  holds  true  of  individual 
muscles. 

Without  doubt,  during  muscle  activity  there  is  a  constant 

1  This  sketch  of  the  fatigue  processes  is  such  as  appears  preliminary  to  the  formulation  of 
a  causal  law  of  fatigue  underlying  industrial  accidents.  Only  the  material  germane  to  a  clear 
understanding  of  the  chapters  which  follow  is  presented  here. 

1  "Le  savant  professeur  (Mosso)  nous  montre  la  lutte  inevitable  fatale,  entre  la  machine 
puissante,  infatigable  et  aveugle  et  1'ouvrier  charge  de  la  conduire,  de  la  guider,  mais  qui  lui, 
organisme  vivant,  est  soumis  aux  lois  de  la  fatigue  et  de  1'epuisement." — P.  Langlois,  Introd., 
trans,  of  Mosso's  La  fatigue  intellectuelle  (Paris,  1904),  12. 

J  F.  S.  Lee,  "The  Nature  of  Fatigue,"  Pop.  Sci.  Mon.,  LXXVI,  185, 186. 


8  RELATION  OF  FATIGUE   TO   INDUSTRIAL  ACCIDENTS 

drain  upon  the  material  from  which  muscle-energy  is  obtained.4 
There  is  a  growing  loss  of  power  to  absorb  nutriment  from  the 
blood,  and  a  continual  tearing  down  without  equal  building  up. 
After  repeated  muscle  contractions,  the  processes  of  katabolism 
(tearing  down)  are  in  excess  of  those  of  anabolism  (building 
up)  ;  and  prolonged  muscular  activity  is  accompanied  by  an 
"exhaustion  of  energy-yielding  material/'  It  should  be  added 
that  this  exhaustion  process  goes  on  not  only  in  the  groups  of 
muscles  which  are  being  visibly  used,  but  also  in  the  groups  of 
muscles  in  different  parts  of  the  body  which  are  held  tense  and 
unrelaxed  in  guiding  the  groups  of  visibly  working  muscles. 

Besides,  the  mentioned  structural  changes  which  accompany 
work5  occur  not  only  in  muscles  but  in  nerve-cells.  Physio- 
logical evidence  indicates  that  during  mental  and  muscular  ac- 
tivity nerve-cells  undergo  actual  structural  changes.6  (a)  The 
nucleus  of  the  nerve-cell  shows  marked  decrease  in  size;  it 
changes  from  a  smooth  and  round  to  a  jagged,  irregular  outline ; 
it  loses  its  open,  reticulate  appearance,  (b)  The  protoplasm  of 
the  nerve-cell  shows  a  slight  shrinkage,  and  undergoes  vacuola- 
tion.  (c)  The  cell  capsule  suffers  a  decrease  in  the  size  of  its 
nuclei.  These  results  were  obtained  from  a  study  of  spinal 
ganglion  and  brain-cells  electrically  stimulated  and  of  those  in 
a  state  of  fatigue  produced  normally.  For  certain  of  these 
nerve-cells,  Hodge  found  that  a  period  which  varied  from  seven 
to  twenty-four  hours  was  necessary  before  the  cells  returned  to 
their  previous  shape  and  appearance. 

Guerrini's  experiments  corroborated  Hodge's  results.  He  ex- 
amined microscopically  the  brain-cells  of  animals  fatigued  by 
muscular  work.  The  more  the  animal  had  been  fatigued 

the  more  profoundly  altered  the  nerve-cells  of  its  cerebral  or  cerebellar  cor- 
tex were  found  to  be.  These  are,  briefly,  the  modifications  which  fatigue 

4  W.  H.  Howell,  A  Text-book  of  Physiology  (Saunders  Co.,  1909),  71. 

*  It  is  not  intended  to  make  a  definite  distinction  here  between  mental  and  muscular 
fatigue.  In  all  forms  of  hazardous  labor  the  mental  and  muscular  factors  are  both  inextricably 
involved  as  parts  of  one  bodily  process,  but  of  course  in  varying  degrees. 

'See  D.  F.  Hodge,  "A  Microscopical  Study  of  Changes  Due  to  Functional  Activity  in 
Nerve  Cells,"  Jour,  of  Morpkol.,  VII,  95-168;  also  "Some  Effects  of  Electrically  Stimulating 
Ganglion  Cells,"  Amer.  Jour,  of  Psych.,  II,  376-402;  also  A.  G.  Levy,  "Fatigue  of  the  Cerebral 
Motor  Cortex,"  Brit.  Med.  Jour.  (1900),  741. 


EMORY  S.   BOGARDUS  9 

produces  on  the  microscopic  structure  of  the  nerve-cell,  and  more  evidently 
in  that  of  the  cerebral  than  in  that  of  the  cerebellar  cortex,  and  most  of  all 
in  the  structure  of  those  nerve-cells  which  correspond  to  the  motor  zones.7 

This  progressively  exhaustive  chemical  process  has  another 
significant  phase  for  this  paper.  As  a  result  of  his  experiments, 
Ranke  came  to  the  belief  that  certain  substances  which  inhibited 
the  power  of  muscular  contraction  were  formed  as  a  result  of 
the  chemical  processes  occurring  during  contraction.  He  named 
these,  "fatigue  substances"  ("ermiidenden  Stoffe").8 

In  the  extracts  of  normal  muscle,  parcolactic  acid  (C3H6O3) 
is  found  but  slightly,  while  the  amount  greatly  increases  during 
muscle  activity.  Mosso  calls  attention  to  the  fact  that  before 
the  close  of  the  i8th  century  Lavoisier  and  Sequin,  by  a  series 
of  memorable  chemical  analyses,  demonstrated  that  muscular 
work  increased  the  amount  of  carbonic  acid  eliminated  from  the 
system.  A  laborer  expires  nearly  twice  as  much  carbon  dioxid 
during  a  working  day  as  during  a  resting  day.  The  carbon 
dioxid  results  from  the  oxidation  of  the  carbon  found  in  the 
constituents  of  the  muscle.  Monopotassium  phosphate  ( KH2PO4 ) 
is  another  of  the  important  and  definitely  determined  fatigue  sub- 
stances.9 These  substances  seemed  to  be  formed  also  in  the 
nerve-cell  during  activity.10 

In  the  next  place,  the  fatigue  substances  mentioned  exert  a 
poisonous  and  paralysing  effect  upon  the  whole  organism.  Both 
parcolactic  acid  and  carbon  dioxid  "when  in  any  but  small  quan- 
tity are  inimical  to  protoplasmic  activity,  and  furthermore,  .... 
a  muscle  under  their  influence  shows  the  very  same  physical 
symptoms  that  are  shown  by  a  muscle  fatigued  through  work." 
After  investigating  a  large  amount  of  testimony  from  physicians 
and  physiologists,  both  European  and  American,  Brandeis  and 
Goldmark  state: 

They  [the  unexpelled  products  of  fatigue]  circulate  in  the  blood,  poison- 
ing brain  and  nervous  system,  muscles,  glands,  and  other  organs  until  normally 

removed  by  the  oxygen  of  the  blood,  by  the  liver  or  kidneys When 

they  exceed  their  physiological  or  normal  amount,  exhaustion  results 

7  Guido  Guerrini,  "Preliminary  Account  of  the  Influence  of  Fatigue  on  the  Structure  of 
the  Nerve-Cells,"  Lancet,  II,  1087. 

1 J.  Ranke,  Tetanus  (Leipzig,  1865),  chap,  xv,  "Die  einzelnen  ermudenden  Stoffe." 
'  Howell,  op.  cit.,  70.  10  Ibid.,  139. 


10  RELATION  OF  FATIGUE   TO  INDUSTRIAL  ACCIDENTS 

In  extreme  instances  of  overexertion  death  results,  not  from  sheer  ex- 
haustion of  the  heart,  but  from  chemical  poisoning  due  to  the  unexpelled 
products  of  fatigue.11 

In  this  connection,  Dr.  H.  B.  Favill  says : 

Any  living  organism  will  die  promptly  if  the  waste  products  (including 
the  fatigue  substances)  from  its  life  processes  accumulate Laboratory- 
research,  verified  by  many  competent  observers,  indicates  that  there  are 
created  in  the  process  of  muscular  work  ....  substances  of  a  nature  dis- 
tinctly poisonous.12 

Besides  the  fatigue  substances  mentioned,  Weichardt  states 
that  muscular  contraction  produces  a  definite  toxin  (keno- 
toxin).13  He  found  kenotoxin  in  the  muscle  juices  ("Muskel- 
preszsaft") ;  and  in  addition  to  the  known  fatigue  substances. 
When  injected  into  an  animal,  kenotoxin  produces  fatigue;  in 
large  doses  it  causes  death  ("wirkte  er  ermiidend  und  in  groszen 
Doses,  todtlich").  Weichardt  has  definitely  isolated  both  keno- 
toxin and  its  antitoxin  ("beide  Substanzen,  habe  ich  isoliert 
dargestellt  und  zu  ausgedehnten  Versuchsreihen  verwendet")- 
These  results  have  been  verified  by  Dr.  Wolff-Eisner.14  They  add 
weight  to  the  fact  that  the  known  fatigue  substances  possess  a 
toxic  and  paralyzing  nature. 

It  appear®  that  the  fatigue  poisons  accumulate  first,  not  in 
the  muscles  actually  moving  but  in  the  groups  of  tense,  non- 
moving  muscles,  which  are  used  in  guiding  the  given  activity. 
These  muscles  are  poorly  irrigated.  But  sooner  or  later  the 
fatigue  substances  accumulate  in  the  moving  muscles,  even  though 
these  are  better  irrigated.  The  toxins  also  circulate  in  the  blood 
throughout  the  body.  Howell  describes  the  twofold  chemical 
process  accompanying  work  as  (a)  an  exhaustion  of  energy- 
yielding  material,  and  (b)  an  accumulation  of  the  products  of 
katabolism  (the  fatigue  substances).15  Verworn  refers  to  the 

11 L.  D.  Brandeis  (assisted  by  Josephine  Goldmark),  The  Brief  in  Defense  of  the  Ten-Hour 
Law  for  Women  in  Illinois  (1909),  77,  78. 

"  H.  B.  Favill,  "The  Toxin  of  Fatigue,"  Survey,  XXIV,  769. 

13  See  W.  Weichardt,  "Ueber  das  Ennudungstoxin  und  Antitoxin,"  Munch,  med.  Wochenschr., 
LI,   2122-26,  LII,  1234-36;    "Ermudungs-  und  Ueberermuduncsmaszmethoden,"  Deutsche 
Vierteljahrschr.f.  ojfentl.  Gesundheitspjl.,  XXXIX,  324-34- 

14  See  A.  Wolff-Eisner,  "Ueber  Ermudungs-  und  Reduktionstoxine,"  CentralbLf.  Bakteriol., 
i  Abt.,  XL,  634-44- 

15  Howell,  op.  cit.,  71. 


EMORY  S.   BOGARDUS  II 

using  up  of  energy-yielding  material  as  culminating  in  "Erschop- 
fung" — a  literal  exhaustion;  and  to  the  production  of  fatigue 
substances  as  resulting  in  a  state  of  "Ermudung."16  The  change 
that  takes  place  in  the  reaction  of  an  active  muscle,  in  the  size  of 
an  active  nerve-cell,  and  in  the  amount  of  waste  material  thrown 
off  by  the  organism  when  it  becomes  active,  leaves  little  room 
to  doubt  that  there  is  a  direct  relation  between  structural  changes 
and  activity. 

^"  This  conclusion  brings  up  the  related  functional  changes  ac- 
companying work.  For  the  purpose  of  this  istudy,  the  fatigue 
process  may  be  treated  as  centering  around  the  objective  phe- 
nomenon of  increasing  muscular  inaccuracy.  Because  of  the 
using  up  of  muscle  material  and  because  of  the  accumulation  in 
the  muscles  of  the  fatigue-toxins,  a  given  group  of  working  mus- 
cles gradually  become  less  able  to  respond  to  the  demands  made 
upon  them  by  the  psychical-neural  apparatus.  If  rapidly  repeated 
stimuli  of  equal  strengths  at  equal  intervals  be  applied  to  a  mus- 
cle, it  is  found  that  at  first  the  contractions  increase  in  extent 
(forming  the  "treppe"),  that  after  a  certain  period  the  contrac- 
tions begin  to  diminish  steadily  in  height  until  finally  the  muscle 
will  fail  to  respond  to  the  stimulus.  This  progressive  loss  of  ir- 
ritability in  the  muscle,  caused  by  repeated  activity,  has  been 
designated  as  fatigue.17 

Ergograph  experiments  (where  the  stimulation  of  the  muscle 
is  not  artificial,  but  voluntary)  show  that  after  a  state  of  complete 
fatigue  has  been  reached  with  a  given  task,  a  very  long  interval 
is  necessary  for  the  muscle  to  make  complete  recovery.18  Mosso 
lays  stress  on  the  fact  that  Professor  Maggiora  proved  that  two 
hours'  rest  is  necessary  before  the  fatigue  traces  are  completely 
removed  from  the  flexor  muscles  of  the  fingers  after  they  have 
been  exhausted  by  a  series  of  contractions  in  the  ergograph.19 

Maggiora  found  that  the  last  smaller  contractions  of  muscles 
are  more  exhaustive  than  the  first  large  contractions.20  After 

'*  Max  Verworn,  Allgemeine  Physiologic  (Jena,  1909),  557. 
17  Howell,  op.  cit.,  34,  35. 

11  Ibid.,  49.  The  ergograph  is  a  special  instrument  devised  by  Mosso,  by  means  of  which 
the  muscle  is  given  a  specific  work  to  do,  such  as  lifting  a  weight. 

"A.  Mosso,  Fatigue  (Paris,  1904),  trans,  by  the  Drummonds,  150. 

"  A.  Maggiora,  "Ueber  die  Gesetze  der  Ermudung,"  Arch.f.  Anat.  u.  Physiol.  (1800),  213. 


12  RELATION  OF  FATIGUE   TO  INDUSTRIAL  ACCIDENTS 

muscles  are  completely  fatigued,  still  further  efforts  to  contract 
them  greatly  prolong  the  period  of  complete  recovery.  Work 
which  calls  for  contractions  of  tired  muscles  is  much  more  in- 
jurious ("viel  schadlicher")  than  greater  muscular  tasks  under 
normal  conditions.21  Verworn  states  that  a  fatigued  muscle  re- 
quires a  considerably  longer  time  ( "unvergleichlich  mehr  Zeit") 
for  relaxation  than  does  a  normal  muscle.22  It  is  the  long  in- 
terval of  recovery,  a  period  unduly  long  for  the  removal  of  the 
katabolic  products  due  to  the  activity  of  a  single  muscle,  which 
leads  to  the  belief  already  cited  that  fatigue  is  partly  due  to  con- 
sumption of  muscle-material  itself,  which  has  to  be  replaced  by 
anabolic  or  building-up  processes  before  the  muscle  is  entirely 
free  from  fatigue  effects.23 

Other  things  being  equal,  the  rate  at  which  the  working  mus- 
cle becomes  less  responsive  to  stimulation  depends  (a)  upon  the 
rapidity  and  (b)  upon  the  difficulty  of  the  given  piece  of  work. 
Kronecker  found  that  the  more  rapid  is  the  rhythm  in  which  mus- 
cular contractions  are  produced,  the  more  rapidly  does  the  height 
of  these  contractions  diminish;  and  vice  versa.24  By  using  the 
ergograph,  Winfield  S.  Hall  found  that  if  a  muscle  be  given  a 
load  proportional  to  the  actual  strength  of  the  muscle  and  if 
the  muscle  be  allowed  to  rest  from  the  strain  of  the  weight 
during  the  period  of  relaxation,  the  time  of  the  fatiguing  process 
may  be  indefinitely  prolonged.25 

Not  only  do  working  muscles  become  less  able  to  respond  to 
stimulation  because  of  fatigue,  but  they  receive  less  and  less  effi- 
cient stimulation  from  the  psychical-neural  apparatus.  It  appears 
that  with  the  exhaustion  of  energy-giving  material  and  with  the 
accumulation  of  the  toxic  fatigue  substances  in  the  parts  used 
and  in  those  portions  of  the  muscles  located  at  any  place  in  the 
body  that  are  under  tension  in  guiding  the  activity  of  the  mus- 
cles that  are  working,  inhibitory  impulses  ascend  along  the  affer- 
ent fibers,  with  which  every  muscle  and  tendon  is  supplied,  to 

"  Op.  cit.,  211.  "  Max  Verworn,  op.  tit.,  548. 

"  W.  H.  Howell,  op.  tit.,  71. 

14  See  C.  S.  Yoakum,  An  Experimental  Study  of  Fatigue  (The  University  of  Chicago  Press, 
1009),  3. 

ts  W.  S.  Hall,  Bulletin  (Northwestern  Medical  School,  Chicago). 


EMORY  S.   BOGARDUS  13 

the  motor  centers  of  the  cortex  and  cord.  Myers  says  that  the 
afferent  fibers  running  from  the  muscular  (and  other)  tissues 
of  the  body  to  terminate  around  the  cells  of  the  motor  nuclei  of 
the  cord,  bulb,  and  mid-brain,  play  an  important  part  in  reflexly 
co-ordinating  muscular  action.26  The  various  motor  centers  of 
the  cord  which  control  the  movements  of  flexion  and  extension 
are  alternately  excited  or  inhibited,  owing  to  the  play  upon  them 
of  afferent  impulses  peripherally  derived  from  the  movements 
themselves.  Whatever  disturbs  these  afferent  impulses  disturbs 
muscular  co-ordinations.  The  using  up  of  muscle  material  and 
the  accumulation  of  fatigue  substances  appear  to  increase  the 
inhibitory  action  of  afferent  impulses. 

The  neural  apparatus  also  becomes  less  efficient  in  guiding 
the  working  muscles  because  of  the  structural  changes  going  on 
in  the  nerve-cells.  Dearborn  says  that  nerve-cells  do  become  ex- 
hausted progressively,  however  slowly,  even  in  cases  where  their 
blood-supply  is  ample  and  their  vigor  normal.27  Tigerstedt  says 
that  by  a  method  especially  adapted  to  the  purpose  it  may  be 
shown  that  the  nervous  mechanism  is  being  greatly  strained  be- 
fore there  is  any  sign  of  fatigue  in  the  external  work  done.28 
In  summing  up  the  situation  regarding  nerve-cell  fatigue,  it  may 
be  said  that  it  seems  probable  that  under  normal  conditions  some 
portions  of  the  nerve  centers  remain  in  more  or  less  constant 
activity  during  the  day  without  showing  a  marked  degree  of 
fatigue,  just  as  muscles  remain  in  a  more  or  less  continuous  state 
of  contraction  throughout  the  waking  period.29  But  when  the 
nerve  centers  are  strongly  stimulated  the  fatigue  is  more  marked 
"because  the  processes  of  repair  in  the  nerve  centers  cannot  then 
keep  pace  with  the  processes  of  consumption  of  materials."30 

Another  factor  which  affects  the  efficiency  of  the  neural  appa- 
ratus in  guiding  the  active  muscles,  has  been  mentioned,  namely, 
the  poisoning  and  paralyzing  effect  of  the  fatigue  substances 

*  C.  S.  Myers,  Experimental  Psychology  (Longmans,  Green  &  Co.,  1909),  186. 

37  G.  V.  N.  Dearborn,  "On  the  Fatigue  of  the  Nerve  Centers,"  Psych.  Rev,,  IX,  182;  see 
also  W.  H.  Burnham,  "The  Problem  of  Fatigue,"  Amer.  Jour,  of  Psych.,  XIX,  385. 

*« R.  Tigerstedt,  A  Text-book  of  Human  Physiology  (Appleton,  1006),  trans,  by  Murlin, 
446. 

"Howell,  op.  cit.,  138.  "Ibid. 


14  RELATION  OF  FATIGUE   TO   INDUSTRIAL  ACCIDENTS 

which  circulate  through  the  brain  and  other  centers  of  control. 
The  structural  and  functional  fatigue  changes  which  have  been 
described  may  be  briefly  summarized  at  this  point.  Not  only  do 
muscles  become  less  responsive  to  stimulation  (because  of  the 
using  up  of  energy-giving  material  and  because  of  the  paralyzing 
effects  upon  them  of  the  fatigue  substances),  but  the  muscles 
receive  less  and  less  efficient  stimulation  from  the  neural  appa- 
ratus (because  of  the  effects  upon  the  neural  apparatus  by  the 
inhibitory  impulses  from  both  the  tense  and  the  moving  muscles, 
by  the  structural  changes  in  the  spinal  ganglion  and  central  nerve- 
cells,  and  by  the  poisonous  fatigue  substances  circulating  through 
the  higher  neural  centers). 

The  combined  effects  of  these  forces  result  in  increasing  mus- 
cular inaccuracy.  Muscular  co-ordinations  become  seriously  ham- 
pered and  irregular.  The  loss  of  control  over  the  muscular 
co-ordinations  consists  first  in  "the  immeasurably  short  shifts 
and  'blockings'  of  the  more  finely  adjusted  musculature  .... 
on  to  the  grossest  muscular  contractions  that  finally  cease  to 
respond  to  the  effort  of  the  will.5'31 

Loss  of  muscle  control  as  indicated  by  the  progress  from 
blocking  of  the  more  finely  adjusted  musculature  on  to  failure 
to  make  the  grossest  muscular  contractions  is  not  adequately 
represented  by  a  continuous  descending  slant.  Increasing  fatigue 
when  brought  to  the  notice  of  the  worker  leads  to  tempo rary 
spurts,  that  is  to  say,  to  an  increase  in  the  volitional  strain  or  at- 
tention which  he  brings  to  bear  on  his  task.  Although  the  fatigue 
process  may  go  on  for  a  time  unnoticed,  it  sooner  or  later  appears 
in  consciousness  in  the  form  of  "sensations."  These  sensations 
may  arise  first  as  feelings  of  effort,  then  as  feelings  of  strain, 
then  as  sensations  of  fatigue.32  The  fatigue  sensations  are  warn- 
ings. They  indicate  that  the  organism  demands  "a  shift  in  the 
working  mechanism."  By  tremendous  effort,  a  fatigued  worker 
may  for  a  short  time  bring  to  his  labor  a  striking  degree  of  vo- 
litional attention. 

These  spurts  appear  irregularly,  and  there  are  alternating 
and  irregular  periods  of  depression  or  bad  spells  -when  the  worker 

»'  Yoakum,  op.  cit.,  114.  Ja  Ibid.,  117. 


EMORY   S.   BOGARDUS  15 

is  less  able  to  give  attention  and  when  the  co-ordinations  are  less 
likely  to  be  .correct  than  during  the  periods  of  volitional  strain. 
Beyond  doubt,  the  periods  of  depression  are  due  to  flagging 
interest  and  increasing  fatigue.33  Hence,  during  uninterrupted 
work  and  as  soon  as  fatigue  effects  predominate  over  skill  due  to 
practice,  there  sets  in  an  irregularly  decreasing  control  over  mus- 
cle co-ordinations.  The  time  at  which  fatigue  is  likely  to  over- 
come practice  during  a  given  period  of  work  depends  among  other 
things  upon  the  rate  and  difficulty  of  the  work,  as  already  noted, 
for  the  given  individual.  At  the  beginning  of  a  period  of  unin- 
terrupted work  there  is  likely  to  be  uncertain  muscle  control,  due 
to  the  necessity  of  getting  "warmed  up"  and  occasionally  to 
nervous  excitement  attendant  upon  beginning  a  piece  of  work. 
Then  for  a  certain  length  of  time  the  muscle  control  is  likely 
to  be  good — due  to  practice  effects.34  When  practice  gain  is 
overcome  by  fatigue  effects,  then  muscular  inaccuracy  becomes 
a  developing  and  important  factor.  During  this  period  effort  is 
expended  in  waves  of  force  that  approximate  what  Treves  calls 
the  irregular  progress  of  mental  fatigue  rather  than  the  regular 
decline  of  muscle  power.35 

Muscular  inaccuracies  may  be  of  two  kinds :  one  may  keep  up 
with  the  rhythm  of  work  and  make  spatial  maladjustments;  or 
one  may  make  accurate  spatial  movements,  and  fall  behind  the 
rhythm;  or  one  may  do  both.  Thus  muscular  inaccuracies  may 
be  not  only  of  a  spatial  nature,  but  may  involve  a  time  element  as 
well.  Mosso  says: 

The  time  of  physiological  reaction  ....  is  the  name  given  to  the  inter- 
val between  the  occurrence  of  an  electric  spark,  for  instance,  and  our  giving 
some  sign  of  having  perceived  it,  say  by  touching  an  electric  button  on  which 
our  hand  rests.  This  short  space  of  time  ....  represents  the  delay  which 
takes  place  before  we  take  account  of  one  of  the  most  simple  forms  of  per- 
ception  Fatigue  has  great  influence  on  the  duration  of  this  reaction 

time.  When  such  measurements  are  repeated  without  an  interval  for  rest, 
the  time  before  the  response  is  given  gradually  increases.86 

M  Myers,  op.  cit.,  194. 

34  A.  Binet,  La  fatigue  intettectuelle  (Paris,  1898),  334;  also  E.  Kraepelin,  Philos.  Studien, 
XIX,  459-507. 

"  Yoakum,  op.  cit.,  42. 
36  Mosso,  op.  cit.,  205. 


1 6  RELATION   OF  FATIGUE   TO   INDUSTRIAL  ACCIDENTS 

A  delay  in  promptness  of  reaction37  and  a  greater  number  of 
faults  of  memory  and  attention  are  noticeable  after  fatigue.38 
It  is  almost  impossible  to  be  attentive  when  the  brain,  for  in- 
stance, is  fatigued.39  The  length  of  time  that  ordinarily  elapses 
before  one  responds  with  the  hand,  for  example,  to  a  touch 
on  the  foot  may  be  doubled  as  a  result  of  the  effects  of  fatigue  on 
attention.40 

^The  effect  of  fatigue  on  attention — which  is  such  an  impor- 
tant factor  in  failure  to  make  accurate  muscular  co-ordinations — 
appears  to  have  its  basis  in  the  difficulty  of  maintaining  the  ten- 
sions which  are  guiding  the  given  activity."  It  is  not  possible  to 
maintain  one  set  of  tensions  long  without  physiological  changes 
taking  place.  And  any  physiological  changes  may  while  they 
are  still  subconscious  be  the  "cue"  for  a  change  of  attention  to 
some  other  topic  of  thought,  a  change  which  may  involve  a  new 
set  of  tensions — and  thus  the  process  continues.  Or,  the  physio- 
logical changes  referred  to  may  come  to  consciousness  in  the 
form  of  sensations  of  fatigue,  and  in  this  case  there  is  a  change 
of  attention  to  the  point  of  origin  or  to  the  sensations  themselves, 
and  vigilance  over  muscular  movements  is  temporarily  suspended. 
V  In  the  case  of  monotonous  division  of  labor  where  the  work- 
man must  attend  continually  to  one  single  uninteresting  point  or 
part  of  a  machine  the  same  neural-muscular  apparatus  must  be 
used,  the  same  tensions  must  be  maintained.  The  difficulty  of 
maintaining  this  situation  with  little  if  any  variation  becomes 
increasingly  great.  If  the  task  in  hand  requires  constant  atten- 
tion, increasing  muscular  inaccuracy  is  likely  to  result — imme- 
diately due  to  the  effects  of  fatigue  on  attention.  The  degree  of 
muscular  inaccuracy  is  determined  partly  by  the  inability  of  mus- 
cles to  respond — according  to  their  state  of  wear  and  tear  and 
to  the  amount  of  fatigue  substances  which  have  accumulated — 
and  partly  by  the  inability  of  the  neural  apparatus  to  attend  to 

17  "Reaction  time  includes  such  phenomena  as  (a)  the  latent  period  in  the  sense  organ, 
(6)  time  of  transmission  along  the  afferent  nerve,  (c)  resultant  processes  within  the  central 
nervous  system,  (d)  time  of  transmission  along  the  efferent  nerve,  and  (e)  the  latent  period  in 
the  muscle."— J.  M.  Cattell,  "The  Time  Taken  by  Cerebral  Operations,"  Mind,  XI,  230. 

11 Z.  Treves,  "Dans  quelle  mesure  peut-on,  par  des  methodes  physiologiques,  etudier  la 
fatigue,'*  etc.,  13*  Cong.  Intern.  d'Hyg.  et  Demog.,  V,  sec.  4,  ques.  3,  p.  37. 

39  Mosso,  op.  cit.,  198.  4*  Ibid.,  205. 


EMORY   S.   BOGARDUS  17 

the  movements  of  the  given  muscles — according  to  the  number 
of  and  the  state  of  the  tensions  which  can  be  relied  upon  in 
guiding  the  given  activity.41 

Muscular  inaccuracy  is  increased  especially  where  the  regular 
effects  of  fatigue  on  attention  are  augmented  by  a  general  con- 
dition of  over  fatigue  of  the  whole  system,  that  is  to  say,  by  a 
state  of  chronic  overfatigue.  Pathological  fatigue  also  results  in 
"increasing  inaccuracy  of  judgment,"42  which  in  turn  increases 
muscular  inaccuracy.  Overwork  blunts  all  the  psychic  activities 
and  diminishes  sensibility;  and  hence  diminishes  the  precision  of 
movements  and  the  exactness  of  the  rhythm.43 

It  has  been  pointed  out  in  this  section  that  uninterrupted  mus- 
cular work  results  in  using  up  of  energy-yielding  material  of 
muscles  and  of  nerve-cells,  and  in  the  accumulation  of  toxic 
waste  substances,  with  an  accompanying  decrease  in  muscle  irrita- 
bility and  activity,  and  inability  of  the  neural  apparatus  to  attend 
to  muscle  movements,  i.e.,  with  a  corresponding  and  increasing 
irregularity  in  the  co-ordination  of  muscular  action.^  The  rate 
X  at  which  these  various  phases  of  the  fatigue  process  takes  place 
is  dependent  on  the  rate  and  difficulty — including  monotony — 
of  the  given  task.J 

If  stated  in  terms  of  the  subjective  conditions  which  the 
writer  believes  quite  generally  precede  accidents,  a  summary  of 
this  chapter  may  be  given  psychological  expression.  The  re- 
sultant and  germane  law  of  fatigue  i^i  Uninterrupted  muscular 
activity  is  accompanied  by  inaccurate  muscular  co-ordinations, 
which  increase  irregularly  and  at  a  rate  largely  determined  by 
the  speed  and  relative  difficulty  of  the  activity  for  the  given 
individual.} 

41  See  Yoakum,  op.  tit.,  99-124;  also  Myers,  op.  cit.,  186  ff. 

4*  E.  W.  Scripture,  "Researches  in  Reaction  Time,"  Yale  Studies,  IV,  12-16,  69-75. 

41 J.  de  Moor,  13.  Intern.  Kongr.f.  Hyg.  u.  Demog.,  Pt.  I,  5,  sec.  4,  ques.  3,  p.  9. 


1 8  RELATION  OF  FATIGUE   TO   INDUSTRIAL  ACCIDENTS 

III.    RELATED  INDUSTRIAL  CAUSES  OF  ACCIDENTS 

After  a  study  of  the  related  subjective  processes  accompany- 
ing work  had  been  made  and  after  the  formula  given  at  the  close 
of  section  II  had  been  determined  upon,  the  writer  supplemented 
a  previous  limited  experience  by  spending  considerable  time  in 
visiting  factories  and  shops  in  and  about  Chicago.  The  purpose 
was  to  test  the  conclusions  already  in  mind  and  to  observe  more 
accurately  the  conditions  which  precede  accidents.  Eleven  fac- 
tories and  shops  were  visited,  representing  as  many  forms  of 
industry.1  Permission  was  obtained  to  wander  leisurely  about 
and  thus  unnoticed  to  observe  operatives  of  dangerous  machines 
while  at  work.  About  twenty  types  of  dangerous  machines  were 
found.2  Three  accidents  were  directly  witnessed — two  at  solder- 
ing machines  and  one  at  a  press  and  drill. 

As  a  result  of  these  observations  it  appears  to  the  writer  that 
thejchief  industrial  conditions  leading  up  to  and  culminating  in 
V  accidents  are  those  of  monotony  and  speed  and  of  unrelated 
tension,  kept  up  for  long  hours.  This  process  seems  to  result 
in  increasing  numbers  and  extent  of  muscular  inaccuracies,  which 
in  turn  appear  to  be  the  phenomena  immediately  preceding  acci- 
dents. This  view  in  more  or  less  detail  will  be  supported  in  this 
section. 

Proof  is  hardly  necessary  to  show  that  monotony  and  great 
speed  characterize  the  conditions  under  which  operatives  of 
dangerous  machines  work.  In  most  industries,  labor  is  so  sub- 
divided that  each  worker  has  but  one  small  part  to  do.  This 
part  is  repeated  thousands  of  times  daily.  To  make  a  small 
sickle  section,  for  example,  requires  thirty  operations  by  as  many 
men  and  boys.  Certain  parts  of  this  process  make  vivid  the 
factors  of  monotony  and  speed. 

A  man  feeds  metal  sheets  into  a  machine  that  cuts  them  out  in  a  three- 
cornered  form,  20,000  per  day  ....  one  motion  is  required  for  each  sheet. 

1  These  included  the  packing,  canning,  and  steel  industries;  leather-goods  and  knitting 
establishments;  steel-castings  and  box  factories;  various  wood- working  and  metal- working 
concerns,  and  wagon  shops. 

1  Among  these  types  are  those  represented  by  the  press  and  drill,  the  press  and  die,  revolv- 
ing knives,  saws,  stamping  and  cutting  machines  of  various  forms,  and  soldering  machines. 


EMORY  S.   BOGARDUS  19 

The  two  holes  of  the  sickle  section,  when  punched,  are  slightly  enlarged 
on  one  side  to  receive  the  head  of  the  rivet,  7,000  per  day.  Along  one  side 
of  the  room  in  which  the  edges  of  the  sickle  section  are  beveled  are  arranged 
a  row  of  grindstones  six  feet  across.  In  front  of  these  whirring  stones  sit 
a  line  of  powerful,  heavy-faced  men,  not  a  spark  of  animation  in  their  faces. 
They  are  each  doing  the  same  thing;  they  drop  one  of  these  plates  into  the 
slot  of  the  frame,  shove  the  frame  against  the  rapidly  revolving  stone  and 
then  draw  it  back;  drop,  shove,  draw  back  ....  5,000  times  each  day.  In 
the  room  where  the  sections  are  serrated,  a  row  of  young  men  stand,  feeding 
machines  which  run  at  great  speed  and  with  deadening  noise.  These  machines 
cut  the  teeth  on  the  bevel  edge  of  the  plate,  7,000  plates  a  day. 

These  monotonous,  speeded-up  operations  in  connection  with 
dangerous  machinery  are  found  in  "the  manufacture  of  nearly 
every  article  of  use  or  comfort  with  which  our  lives  are  sur- 
rounded ;  in  the  manufacture  of  that  piano,  the  chair  you  are  sit- 
ting on,  the  watch  in  your  pocket,  the  car  you  ride  in,  the  sewing 
machine,  the  meat  you  ate  for  your  breakfast  this  morning." 

In  the  canning  factories  of  Pittsburgh,  for  instance,  where 
tops  for  cans  are  cut  from  sheets  of  tin,  the  foot-press  operator 
puts  the  sheets  in  the  press,  gauges  it  so  that  it  will  fall  evenly, 
•  gives  a  quick  pressure  of  the  foot  in  order  to  clip  the  tin  for 
each  top.  This  quick  pressure  and  accompanying  hand  move- 
ments are  repeated  "forty  times  a  minute,  24,000  times  a  day."3 
Ernst  Abbe  points  out  that 

with  this  sameness  ("Gleichformigkeit")  and  continually  recurring  monotony 
("Einformigkeit"),  we  also  get  the  continuous  ("fortgesetzte")  fatigue  of 
the  same  organ,  of  the  same  nerve  centers,  and  of  the  same  part  of  the  brain 
....  because  all  that  is  to  be  done,  whether  muscular  or  mental  work,  must 
be  constantly  repeated  ("sich  wiederholen")  in  the  same  manner  from  morn- 
ing to  night,  day  by  day,  and  week  by  week.* 

s  Today,  the  necessary  rapidity  of  monotonous  motions  fa- 
Xtigues  workers  and  causes  accidents.  Dr.  Thomas  Oliver  regrets 
the  attempt  to  americanize  shipbuilding  in  England  for  the  rea- 
son that  this  "rushing"  is  a  cause  of  serious  accidents.5  Pro- 
fessor G.  Pieraccini  and  Dr.  R.  Maffei,  Florence,  state  that  piece- 
work, which  necessitates  higher  speed,  tends,  both  in  itself  and 

*  Eliz.  B.  Butler,  Women  and  the  Trades  (Charities  Pub.  Com.,  1909),  36. 
4  E.  Abbe,  Gesammelte  Abhandlungen  (Jena,  1906),  HI,  225. 
s  T.  Oliver,  Diseases  of  Occupation  (London,  1908),  3. 


20  RELATION  OF  FATIGUE   TO  INDUSTRIAL  ACCIDENTS 

together  with  the  fatigue  that  ensues,  to  favor  the  occurrence  of 
labor  accidents.6  It  is  no  exaggeration  to  say  that  the  pace  kills 
andjnjures  more  people  than  labor  peruse..  To  the  extent  that 
the  stupefying  effects  of  monotony  and  the  confusion  attendant 
upon  "speeding  up}}  are  added  to  the  regular  development  of  the 
fatigue  process,  loss  of  muscular  control  and  danger  of  accident 
are  increased. 

A  characteristic  phase  of  monotony  and  speed  is  unrelaxed 
tension  of  the  worker.  Arlidge  says  that  the  fatigue  of  machine 
operatives  is  more  the  fatigue  of  watching  than  that  of  working.7 
From  a  psychological  standpoint,  it  is  impossible  to  attend  to 
very  many  things  at  a  time  or  to  attend  to  one  thing  for  very 
long  at  a  time.  It  is  especially  fatiguing  to  keep  the  attention 
on  a  simple  process  which  presents  no  new  phase,  but  which  is 
a  continuous  repetition  of  a  few  simple  movements  hour  by  hour. 
It  is  true,  of  course,  that  these  movements  tend  to  become  auto- 
matic ;  but  when  they  must  be  made  in  close  proximity  to  danger- 
ous and  rapidly  revolving  tools,  a  certain  degree  of  voluntary 
attention  must  be  exercised,  or  else  injury  will  result  during  a 
moment  of  inattention. 

Professor  Henderson  states  that  the  speed  of  saws,  for 
instance,  is  a  -significant  factor  in  increasing  danger,  "because 
the  swift  movement  increases  the  strain  upon  attention  and  so 

X  rapidly  exhausts  nervous  energy."8  The  relaxation  of  tension 
which  sometimes  results  in  serious  injury,  says  Elizabeth  B. 
Butler,  may  be  accounted  for  by  the  hurry  of  the  worker  who 
is  usually  ambitious,  or  by  the  weariness  toward  the  end  of  the 
five  hours'  continuous  work.9 

^  Operatives  of  machinery  become  accustomed  to  the  presence 
of  danger  and  hence  less  on  their  guard  against  the  effects  of 
fatigue  on  attention.  Cadbury  says  that  workers  accustomed  to 
danger  are  apt  to  look  away  to  talk  to  their  companions  and  in 

*  See  Brandeis  and  Goldmark,  Ten-Hour  Law  for  Women,  75. 

T  J.  T.  Arlidge,  The  Hygiene,  Diseases  and  the  Mortality  of  Occupations  (London,  1892). 
»C.  R.  Henderson,  "Wood-Workers  and  Their  Dangers,"  World  To-Day,  XIX,  975. 

•  Eliz.  B.  Butler,  op.  cit.,  22  . 


EMORY  S.    BOGARDUS  21 

a  moment  of  relaxed  tension  the  hand  is  caught  under  the  ma- 
chine. 

The  incessant  noise  of  the  machinery,  the  excessive  monotony  of  the 
{/  work,  and  above  all,  the  long  hours,  which  are  too  often  spent  in  an  ill- 
lighted  and  ill-ventilated  atmosphere — all  tend  to  produce  a  depressing  and 
deadening  effect  which  cannot  fail  to  destroy  the  alertness  of  attention.10 

In  the  steel  mills,  for  example,  an  alert  mind  is  the  first  re- 
quirement for  safety.11  There,  as  elsewhere  in  connection  with 
dangerous  work,  attention  is  focused  more  on  the  proper  accom- 
plishment of  the  work  than  on  self -protection.  But  attention 
to  the  matter  of  self -protection  in  steel  mills  is  comparable  to  an 
attempt  to  dodge  bullets  on  the  battlefield.  Neither  a  steel- 
worker  nor  a  soldier  of  that  type  can  long  retain  the  respect  of 
his  fellows.  Attention  to  self -protection  is  bound  to  be  sec- 
ondary and  incidental;  but  to  insure  the  workman's  safety  it 
must  be  constant  and  keen.  However  instinctive  this  vigilance 
may  be,  it  cannot  be  considered  unfailing.  The  speed^and  in- 
tensity of  the  work,  the  .heat  and  noise  of  the  steel  mill,  TEe 
weariness  of  the  workers,  "all  these  things  tend  to  numb  the 
faculties  most  needed  for  protection."12 

As  a  result  of  continuous  and  unrelaxed  tension,  the  fatigue 
processes  go  on  insidiously.  The  onset  of  fatigue  is  often  un- 
perceived.  The  tension  in  modern  industry  calls  out  the  voli- 
/  tional  power  which  urges  on  a  fatigued  worker,  intensi- 
fies application,  and  minimizes  the  sensation  of  effort,  thus 
concealing  fatigue.  Kirkpatrick  emphasizes  the  fact  that  a  per- 
son often  does  not  feel  weary  after  his  power  to  act  has  been 
very  much  decreased.13  The  distinction  which  must  be  made 
between  the  sensations  which  supervene  during  the  performance 
of  the  work  and  the  lowered  capacity  for  work  as  shown  ob- 
jectively by  diminution  in  the  amount  of  work  executed  is  well 
known.  Rivers  says  that  there  may  be  complete  absence  of  any 
sensations  of  fatigue,  when  the  objective  record. shows  that  the 

"  Edw.  Cadbury  and  others,  Women's  Work  and  Wages  (The  University  of  Chicago  Press 
1907),  S3- 

"  Crystal  Eastman,  Work-Accidents  and  the  Law  (Charities  Pub.  Com.,  1910),  91. 

"Ibid. 

1JE.  A.  Kirkpatrick,  Fundamentals  of  Child-Study  (Macmillan,  1009),  322. 


22  RELATION  OF  FATIGUE   TO   INDUSTRIAL  ACCIDENTS 

work  is  falling  off  in  quantity,  or  in  quality,  or  in  both.14  The 
curve  of  organic  fatigue  follows  a  different  outline  than  that 
which  represents  the  production  of  voluntary  work.15 

Workmen  are  generally  ignorant  of  the  difference  between 
the  subjective  development  of  fatigue,  and  its  objective  corre- 
lates. Unrelaxed  tension  in  modern  industry  makes  continuous 
and  terrible  demands  on  the  human  volitions.  These,  in  turn, 
so  intensify  application  and  minimize  warnings  of  overfatigue 
that  the  worker  in  the  dangerous  trades  may  suddenly  through 
inaccurate  movements  find  himself  handicapped  for  life,  or  the 
wife  and  children  may  receive  the  unexpected  message  that  their 
breadwinner  has  given  up  his  life  while  serving  at  the  post  of 
duty. 

The  terrific  mental  strain  due  to  monotony  and  speeding  up 
js  doubly  vicious  because  of  the  fact  of  long  hours,  After  a 
certain  period  of  time,  varying  in  length  with  different  indi- 
viduals, unrelaxed  tension  cannot  be  consistently  maintained,  un- 
certainty of  movements  increases,  and  danger  of  accidents  multi- 
plies. After  making  a  careful  investigation  of  work-hours,  the 
National  Conservation  Commission  says :  "The  present  working 
day  from  a  physiological  standpoint  is  too  long,  and  keeps  the 
majority  of  men  and  women  in  a  continual  state  of  overfatigue.16 
....  The  manual  worker  through  fatigue  caused  by  long  hours 
is  in  a  continual  state  of  overexertion!}Yl 

The  situation  is  especially  grave  when  the  men  and  women 
kept  in  a  continual  state  of  overfatigue  because  of  long  hours 
are  operatives  of  dangerous  machinery.  Further,  in  many  in- 
dustries where  danger  exists,  the  long  hours  of  regular  employ- 
ment are  supplemented  by  demands  for  "overtime"  work  during 
certain  parts  of  the  year.  In  Pittsburgh,  for  example,  Elizabeth 
Butler  found  that  many  canning  factories  work  every  night  until 
ten  o'clock  during  the  busy  season,  making  a  working  week 
of  over  72  hours.18  One  manager  admitted  that  the  girls 

M  W.  H.  Rivers,  The  Influence  of  Alcohol,  etc.,  on  Fatigue  (London,  1908),  2. 

15  T.  Oliver,  Dangerous  Trades  (London,  1902),  117. 

16  Senate  Document  No.  419,  6ist  Cong.,  2d  sess.  (1910),  626. 

17  Ibid.,  666. 

18  Eliz.  B.  Butler,  op.  cit.,  39,  40. 


EMORY   S.    BOGARDUS  23 

under  his  direction  " worked  75  hours  a  week  for  two  months 
every  year."  He  added  that  the  factory  inspectors  generally 
did  not  interfere;  that  they  usually  come  around  in  September 
and  after  the  holidays,  and  "they  never  see  any  overtime."19  In 
another  factory  where  foot-press  work  was  the  chief  type  of 
labor,  Miss  Butler  found  that  the  employees  are  sometimes 
forced  to  work  twelve  and  fourteen  hours  and  "accidents  are 
so  frequent  that  the  place  has  been  characterized  as  a  butcher 
shop."20  As  another  more  or  less  typical  illustration,  a  "hinge 
factory"  may  be  mentioned  where  "overtime"  work  until  half- 
past  eight  is  demanded  almost  throughout  the  year,  there 
being  no  regular  alternation  of  busy  and  slack  seasons,  but  change 
according  to  orders.21  This  irregularity  is  peculiarly  true  of  the 
laundries,  where  in  the  latter  part  of  the  week  "overtime"  often 
lasts  till  eleven  o'clock  at  night  and  later.22 

In  regard  to  railway  employees,  Crystal  Eastman  quotes  a 
yard-master  as  follows : 

Yardmen  now  usually  work  twelve  hours,  but  when  the  yards  are 
pressed,  they  often  work  the  brakemen  the  sixteen-hour  limit.  And  when 
a  man  works  sixteen  hours  at  a  stretch,  it  often  means  that  he  has  been 
awake  eighteen  or  twenty  hours,  because  there  is  a  rule  that  a  man  must  be 
called  two  and  a  half  hours  before  he  goes  on  duty.2* 

In  the  steel  industry,  the  working  day  is  usually  twelve  hours. 
A  typical  steel- worker  says : 

I've  been  twenty  years  at  the  furnaces  and  have  been  working  a  twelve- 
hour  day  all  that  time,  seven  days  in  the  week We  work  that  way 

for  two  weeks  and  then  we  work  the  long  turn  and  change  to  the  night  shift. 
The  long  run  is  when  we  go  on  at  seven  Sunday  morning  and  work  through 
the  whole  twenty-four  hours  up  to  Monday  morning.8* 

John  A.  Fitch  says  that  in  1907  he  could  find  only  about  120 
eight-hour  men  among  the  17,000  employees  in  the  three  largest 
plants  of  the  Carnegie  Steel  Company  in  Allegheny  County — a 

"  Ibid.,  53.  *°  Ibid.,  233.  "  Ibid.,  225. 

"  See  Clark  and  Wyatt,  "Women  Laundry  Workers  in  New  York,"  McClure's,  XXXVI, 
401-13- 

23  Crystal  Eastman,  op.  cit.,  33. 

34  John  A.  Fitch,  The  Steel-Workers  (Charities  Pub.  Com.,  1911),  170. 


24  RELATION  OF  FATIGUE  TO  INDUSTRIAL  ACCIDENTS 

trifle  less  than  three- fourths  of  i  per  cent ;  "the  prevailing  work- 
day is  twelve  hours  for  steel-workers."  But  the  machinists  being 
also  repair  men  are  sometimes  obliged  to  work  much  longer,  occa- 
sionally "a  continuous  twenty-four-hour  period,  while  sometimes 
the  men  work  thirty-four  hours  or  longer  without  rest."25 

Under  normal  conditions,  fatigue  would  be  overcome  by  ade- 
quate periods  of  rest,  but  in  modern  industry  the  workman  is 
often  denied  the  satisfaction  of  the  physiological  demands  of 
fatigue.  The  human  organism  is  so  constructed  that  on  rare 
occasions  great  reserve  powers  can  be  called  out.  Modern  in- 
dustrial labor  is  such  that  the  reserve  forces  are  called  out  daily. 
Mental  strain  and  muscular  fatigue  are  phases  of  the  general 
fatigue  process  which  develops  with  accumulative  force,  not 
only  in  the  course  of  a  day-period,  but  week  by  week.  Jo- 
teyko  says  that  it  appears  certain  that  fatigue  accumulates  "s'ac- 
cumule  progressivement"  in  the  organism.26  "Fatigue  is 
viciously  progressive,"  says  Dr.  Favill.27  The  actual  structural 
changes,  the  impairment  of  the  nutritive  processes,  the  accumu- 
lation of  poisonous  products  when  taken  together  make  up  "an 
overwhelming  incubus  which  no  organism  can  long  survive."28 

Fatigue  sometimes  starts  a  vicious  circle  which  leads  to  the 
craving  of  and  indulgence  in  means  for  deadening  fatigue. 
Liquor  may  drive  away  temporarily  the  fatigue  sensations,  but 
in  the  end  it  will  leave  the  workman  weaker,  more  subject  ,to 
trembling,  to  uncertain  muscular  control,  and  to  injury. 

Where  fatigue  is  not  balanced  by  adequate  rest  and  nourish- 
ment, a  deficitj-emains  which  is  added  to  daily,  which  accumu- 
lates little  by  little;  and  the  workman  suffers  increased  suscepti- 
bility to  accident.  When  the  workman's  strength  becomes 
debilitated  through  overwork,  he  becomes  incapable  of  atten- 
tion,29 and  defenseless  against  accident. 

Present-day  operation  of  dangerous  machinery  finally  re- 
solves itself  into  a  competition  of  sensitive  human  nerves  and 

"Op.  tit.,  174. 

•*  J.  Joteyko,  "Participation  des  centres  nerveux  dans  les  phenomenes  de  fatigue  muscu- 
laire,"  L'annee  Psych.,  VII,  166. 

>r  H.  B.  Favill,  "The  Toxin  of  Fatigue,"  Survey,  XXIV,  772.  "  Ibid. 

19  Th.  Ribot,  "The  Psychology  of  Attention,"  Open  Court  (1896),  99. 


EMORY  S.   BOGARDUS  25 

muscles  against  relentless  and  insensitive  iron.30  The  greater 
the  number  of  hours  that  machinery  must  be  operated  per  day, 
the  feebler  and  more  uncertain  become  the  human  forces  that 
guide  it.  To  the  machine,  time  is  nothing;  to  the  working  man 
and  woman,  each  hour  that  passes  beyond  a  certain  limit  offers 
increasing  opportunity  of  injury  and  possibility  of  death. 

While  monotony,  speed,  unrelaxed  tension,  together  with  long 
hours,  appear  to  be  the  leading  general  causes  of  industrial  fatigue 
and  hence  of  many  accidents,  it  is  proposed  next  to  determine  if 
possible  the  modus  operandi  of  these  general  causes  in  bringing 
about  accidents.  In  other  words,  what  are  the  concrete,  imme- 
diate conditions  preceding  accidents? 

The  writer  has  had  access  to  the  accident  records  of  the  state 
of  Illinois  for  the  year  ipio.31  These  records  refer  to  accidents 
which  necessitated  that  the  injured  lay  off  from  work  fifteen  days 
or  over,  and  they  apply  to  the  various  manufacturing  industries, 
the  steel  industry,  and  to  many  small  plants  and  factories  in 
Illinois.  Of  the  total  number  of  accident  reports — some  over 
3,000 — which  were  examined,  2,678  applied  to  non- fatal  cases 
and  gave  a  fairly  accurate  description  of  what  happened  preced- 
ing the  given  accidents.  The  remaining  4OO-odd  reports  either 
omitted  a  description  of  the  immediate  cause  or  else  gave  it  so 
inaccurately  as  to  throw  doubt  on  its  value  for  this  analysis. 

The  accident  descriptions  which  apparently  are  accurate  fall 
into  two  general  classes.  Class  A  includes  the  accidents  where 
the  immediate  cause  was  evidently  beyond  the  control  of  the 
injured — due  to  the  breaking  of  machinery,  to  bursting  of 
boilers,  to  chips  of  steel  flying  in  the  air.  Typical  statements 
illustrating  this  general  class  of  accidents,  as  taken  from  the 
accident  reports,  are  subjoined: 

Scaffold  collapsed. 

Bolster  flew  out  from  under  steam  hammer. 

Chip  in  eye. 

Gas  exploded. 

Hot  steam  blew  in  eye. 

J*T.  Oliver,  Dangerous  Trades,  117. 

31 1  wish  to  acknowledge  the  courtesies  shown  me  by  Edgar  T.  Davies  and  his  assistants  in 
the  office  of  State  Factory  Inspection  (Chicago). 


26  RELATION  OF  FATIGUE   TO  INDUSTRIAL  ACCIDENTS 

Flying  nail  struck  eye. 

Struck  in  the  face  by  piece  of  iron  ....  due  to  pulley  breaking. 

Hot  scale  blew  into  eye. 

It  is  beyond  doubt  that  in  the  cases  represented  by  Class  A,  per- 
fect subjective  control  preceding  the  given  accidents  would  not 
have  made  escape  possible. 

Class  B  represents  those  accidents  in  which  loss  of  control, 
varying  from  failure  to  make  fine  co-ordinations  on  to  gross  and 
bungling  co-ordinations  and  to  absence  of  movements  which 
might  have  prevented  injury,  appears  to  have  been  a  factor. 
Class  B  is  illustrated  by  the  following  typical  descriptions : 

Did  not  get  her  hand  away  soon  enough  and  thumb  was  caught  between 
billets. 

Placed  his  finger  too  close  to  the  cutter  in  putting  in  a  piece  of  work. 

Got  his  fingers  under  the  die  when  it  came  down. 

Caught  hand  under  punch. 

In  some  manner  he  got  the  small  finger  of  right  hand  against  the  saw 
while  the  same  was  in  motion. 

Did  not  get  his  hand  out  of  the  way  in  time  and  his  fingers  were  caught 
between  plunger  and  edge  of  socket. 

His  hand  slipped  over  the  guard  and  caught  in  the  knife. 

His  fingers  went  under  the  die  when  he  accidentally  tripped  the  press. 

Caught  his  fingers  in  the  die. 

The  injured  accidentally  placed  his  finger  too  close  to  the  cutter  in  put- 
ting in  a  piece  of  work. 

Automatically  placed  foot  on  treadle  when  tips  of  fingers  were  under  die. 

Hand  slipped  on  to  rip-saw. 

Caught  hands  in  knives. 

Caught  fingers  between  press  and  die. 

Caught  fingers  between  head  of  die  and  material. 

Caught  fingers  in  jointer  while  operating  same. 

Caught  thumb  between  sheet  metal  and  die. 

Her  finger  slipped  into  the  gear  of  her  machine. 

Of  the  2,678  accident  records  which  gave  a  fairly  good  de- 
scription of  what  occurred  immediately  preceding  the  accidents, 
twelve  records  were  of  doubtful  analysis.  Four  hundred  and 
sixty-three  cases  or  17.2  per  cent  belonged  to  Class  B.  Of  the 
fatal-accident  reports  studied  the  number  is  too  small  to  be  of 
much  value.  Twenty  fatal  accidents  or  37.8  per  cent  were  of 
Class  A;  and  forty-one  or  62.1  per  cent  belonged  to  Class  B. 


EMORY  S.   BOGARDUS 


Table  I  shows  that  a  large  percentage  of  non- fatal  accidents  is 
immediately  preceded  by  muscular  inaccuracies.  In  all  cases  of 
Class  B,  it  is  conceivable  that  if  the  injured  had  had  perfect  and 
ready  control  over  muscular  movements  he  would  not  have  suf- 
fered accident. 

TABLE  I 

INDUSTRIAL  ACCIDENTS  CLASSIFIED 


Year  1910 

Doubtful 

Class  A 

Class  B 

Total 

Number 

12 

4.63 

2,203 

2,678 

Percentage 

o  4 

17.  2 

82.2 

IOO 

In  Section  II  it  has  been  shown  that  the  developing  subjective 
fatigue  processes  inevitably  result  in  increasing  muscular  inac- 
curacy; in  the  preceding  paragraphs  of  this  section  it  has  been 
y  further  shown  that  monotony,  speed,  mental  strain  in  connection 
with  long  hours  hasten  the  fatigue  processes  and  hence  greatly 
increase  the  loss  of  muscular  control.  In  this  section  it  is  main- 
tained that  to  the  extent  that  fatigue  is  a  primary  cause  of  mus- 
cular inaccuracies,  82.2  per  cent  of  the  2,678  accidents  studied 
involved  fatigue  as  a  causal  factor. 

This  proposition  is  illuminated  by  the  fact  that  "the  swift 
machinery  of  modern  industry  requires  the  attendants  to  push 
and  guide  the  material  in  close  proximity  to  merciless  cutting 
tools."32  In  Chicago  the  writer  found  twenty  types  of  ma- 
chines in  connection  with  which  the  operatives  were  working  so 
close  to  revolving  saws,  knives,  drills,  rollers,  or  at  machines 
of  the  press  and  die  type  that  the  misplacement  of  the  hand  a 
fraction  of  an  inch  meant  mutilation.  The  three  accidents  which 
the  writer  witnessed  were  exactly  of  this  nature — two  at 
soldering  machines  and  one  at  a  press  and  drill — in  each 
case  a  hand  was  misplaced  a  fraction  of  an  inch  and  came  into 
contact  with  dangerous  parts  of  the  respective  machines. 

At  mangles,  too,  the  danger  is  grave.  What  the  girls  call  "millionaire 
work" — work  that  has  to  come  out  straight — in  contrast  with  "board- 
ing-house" work,  must  be  shoved  up  to  tvithin  a  quarter  of  an  inch  of 
the  cylinder.  Fingers  once  caught  in  such  mangles  are  crushed.  Consider 

33  C.  R.  Henderson,  op.  cit.,  World  To-Day,  XIX,  972. 


28  RELATION  OF  FATIGUE  TO  INDUSTRIAL  ACCIDENTS 

in  connection  with  these  two  points  the  high  rate  of  speed  at  which  the 
girls  feed  the  work  into  the  machine,  and  the  precarious  character  of  their 
work  will  be  realized.38 

From  these  facts  it  is  evident  that  the  slight  slips  and  mis- 
takes which  every  person  makes  are  exactly  the  phenomena  which 
precede  many  serious  accidents  when  they  occur  in  dangerous 
occupations.  "When  a  cook  drops  a  cup,  the  loss  is  a  few  cents; 
when  a  structural  iron-worker  is  guilty  of  no  greater  inattention, 
he  may  lose  his  life."34 

The  thesis  of  this  section  has  been  confirmed  by  a  report 
prepared  by  the  Bureau  of  Labor  which  is  not  off  the  press  at 
this  writing  (April  i,  1911).  The  following  excerpt  is  taken 
from  proof  sheets : 

It  (the  fatigue  process)  gradually  upsets  those  nice  adjustments  of 
the  living  organism  upon  which  depend  efficient  labor  and  the  safety  of  the 
worker.  The  margin  of  safety  in  modern  industry  is  small.  It  is  measured 
too  frequently  by  fractions  of  an  inch.  Reduce  the  alertness  and  the  exact- 
ness with  which  the  body  responds  to  the  necessities  of  its  labor,  and  by  just 
so  much  have  you  increased  the  liability  that  the  hand  will  be  misplaced  that 
fraction  which  means  mutilation* 

Thus  slight  deviations  entail  serious  consequences  and  result 
in  industrial  accidents.  "The  exhausted  workman  no  longer 
has  full  control  over  his  muscles.  His  results  are  less  exact, 
danger  by  accident  increases/'36  Even  the  skilled  laborer  does 
not  work  as  regularly  as  the  machine.  His  ability  to  make  ac- 
curate movements  shows  regularly  returning  shrinkings  as  a 
result  of  the  activity  of  the  neural-muscular  factors.37  This  phase 
of  the  fatigue  problem  has  been  summed  up  by  Felix  Arnold : 

Concentrated  activity,  especially  when  it  involves  motor  control,  usually 
results  in  fatigue.  There  arises  ....  increased  slowness  of  response.  Effi- 
ciency of  attention  begins  to  decline In  simple  reactions,  the  reaction 

time  becomes  longer.  Objects  in  the  field  of  attention  persist  for  a  less  time 
in  the  center  of  control.  On  the  subjective  side,  fatigue  is  felt  as  weariness, 
disinclination  to  persistent  effort,  sensation  of  strain  in  the  muscles,  lack  of 
interest  in  situations  which  normally  are  of  an  impelling  nature,  and  some- 

»  Clark  and  Wyatt,  McClure's,  XXXVI,  402. 

**  Bureau  of  Labor  and  Industrial  Statistics  (Wisconsin),  13th  Bien.  Report,  Part  I,  p.  4. 

"  Senate  Document  No.  645,  v.  n,  p.  42. 

36  H.  Herkner,  Handworterb.  d.  Staatswissensch.  (Jena,  1909),  I,  1215. 

"  E.  Roth,  14.  Intern.  Kongr.f.  Hyg.  u.  Demog.,  II,  611. 


EMORY  S.   BOGARDUS  29 

times  as  pain  in  the  parts  of  the  body  affected.  On  the  objective  side  fatigue 
is  manifested  by  a  general  slackness  and  listlessness  of  the  body  posture,  by 
relaxed  fingers,  and  by  asymmetrical  and  fidgety  movements.  Co-ordina- 
tions become  more  bungling,  incorrect,  and  for  finer  control  often  impossible" 

If  men  and  women  subject  to  industrial  overstrain  are  work- 
ing at  or  near  rapidly  revolving  knives  or  saws,  are  operating 
punches,  presses,  or  drills  at  a  furious  rate  of  speed,  their  chances 
are  good  of  being  counted  among  the  annual  list  (in  the  United 
States)  of  30,000  killed  and  500,000  injured  in  industry.39 

The  law  of  fatigue  as  related  to  accidents  and  given  at  the 
close  of  Section  II  may  be  restated  in  the  light  of  the  facts  of 
this  section  as  follows:  The  irregularly  increasing  muscular  in- 
accuracy  which  accompanies  work  results  in  correlatively  in- 
creasing chances  of  accident. 

It  is  proposed  to  test  this  law  by  further  facts.  In  the  fol- 
lowing section  it  will  be  attempted  to  verify  further,  if  possible, 
the  causal  relationship  existing  between  fatigue,  decreasing  mus- 
cular control,  and  accidents,  by  means  of  several  series  of  con- 
trolled experiments  in  which  various  industrial  conditions  are 
more  or  less  closely  simulated. 

IV.    SOME  CONTROLLED  EXPERIMENTS 

(From  the  Psychological  Laboratory  of  the  University  of  Chicago)* 

Section  II  set  forth  the  fact  that  continued  work  is  accom- 
panied by  increasing  muscular  inaccuracy.  In  Section  III  it 
was  shown  that  these  muscular  inaccuracies  are  the  immediate 
phenomena  preceding  a  large  proportion  of  accidents.  In  order 
to  determine  more  exactly  the  nature  of  the  muscular  inac- 
curacies which  increasingly  accompany  continued  work  and 

**  Felix  Arnold,  Attention  and  Interest  (Macmillan,  1910),  153. 

"  J.  B.  Andrews,  "A  Clinic  for  Industrial  Diseases,"  Survey,  XXV,  269. 

1  Preliminary  to  these  experiments,  the  writer  conducted  two  series  of  experiments  on  the 
typewriter.  The  striking  of  a  typewriter  key  requires  a  definite  muscular  co-ordination.  All 
variations  of  one-half  inch  and  over  from  the  correct  muscle  movement  appear  as  errors  on  the 
typewritten  pages.  These  faulty  co-ordinations  are  similar  in  general  nature  to  the  muscular 
inaccuracies  which  precede  many  industrial  accidents.  The  results  of  the  typewriter  experi- 
ments indicated  clearly  an  irregular  but  marked  increase  in  the  number  of  muscular  errors 
occurring  during  a  given  work-period.  This  increasing  inaccuracy  was  accompanied  by  symp- 
toms of  increasing  fatigue.  But  it  will  be  observed  that  in  experiments  on  the  typewriter,  the 
power  which  runs  the  typewriter  is  intrinsic;  that  is,  the  subject  or  operator  by  his  own  voli- 
tion must  keep  the  typewriter  in  motion.  It  appeared  that  these  experiments  would  have 


30  RELATION  OF  FATIGUE   TO   INDUSTRIAL  ACCIDENTS 

which  result  in  increasing  danger  of  accident,  a  type  of  machine 
for  experimental  purposes  was  designed  which  in  its  operation 
would  combine  the  factors  most  common  to  industrial  conditions, 
namely,  monotony,  speed,  mental  strain — and  which  at  the  same 
time  would  permit  a  computation  of  the  muscular  inaccuracies 
resulting  from  operating  it.2 

Figs,  i  and  2,  will  give  an  idea  of  the  apparatus  used.  The 
part  of  the  machine  designated  x  in  Fig.  i  appears  in  enlarged 
form  in  Fig.  2.  The  letters  a,  b,  c,  d  represent  thin  brass  plates 
so  set  in  the  top  of  the  table  that  their  inner  lines  form  a  square 
of  one-inch  dimensions.  They  do  not  come  in  contact  with  each 
other;  their  upper  surfaces  are  practically  on  a  level  with  the 
upper  surface  of  the  table.  The  letters  a',  b',  c' ,  d'  designate 
another  set  of  brass  strips  whose  inner  lines  are  three-sixteenths 
of  an  inch  from  the  inner  lines  of  a,  b,  c,  d,  respectively.  The 
subject  was  given  wooden  inch  cubes,  one  side  of  each  being 
covered  with  a  thin  brass  plate.  If  the  block  was  accurately 
placed  its  outer  edges — brass  side  down — would  exactly  coincide 
with  the  inner  lines  of  a,  b}  c,  d.  However,  the  outer  edges  of 
the  brass  base  could  extend  over  the  lines  of  a,  b,  c,  d  practically 
three-sixteenths  of  an  inch  in  any  direction  and  the  placement 
would  still  be  counted  as  accurate.  But  the  brass  strips  were  so 
electrically  wired  that  a  and  a',  b  and  b' ' ,  etc.,  represented  the 
termini  of  respective  circuits.  Hence  if  the  brass  base  of  a  block 
for  instance,  was  misplaced  to  the  extent  that  one  of  its  sides 
extended  over  a! ,  as  represented  by  the  dotted  line  r,  an  electrical 
circuit  was  established  and  an  error  was  recorded  on  an  endless 
sheet  of  smoked  paper  carried  by  two  slowly  revolving  Scripture 
drums,  arranged  after  the  manner  of  Yoakum.3  If  the  block 

greater  value  if  conducted  on  a  machine  which  was  run  by  external  power,  e.g.,  by  an  electric 
motor.  In  this  case  the  operator  would  be  required  to  keep  up  with  the  pace  set  by  the  machine, 
and  not  set  his  own  pace. 

It  was  this  problem  which  I  took  to  Professor  James  R.  Angell,  to  whom  I  am  indebted 
for  making  possible  the  experiments  described  in  this  section,  for  designing  a  considerable 
portion  of  the  apparatus,  and  for  many  stimulating  suggestions.  The  apparatus  which  is 
described  in  the  following  pages  was  built  only  after  a  special  study  had  been  made  of  dangerous 
machines  in  industry.  It  was  designed  especially  to  incorporate  as  many  as  possible  of  the 
general  features  of  the  machines  used  in  the  dangerous  trades. 

1  For  the  purposes  of  this  chapter,  these  experiments  have  been  presented  from  a  socio- 
logical point  of  view.  Much  material  is  at  hand  for  a  psychological  discussion. 

J  C.  S.  Yoakum,  An  Experimental  Study  of  Fatigue,  54. 


EMORY   S.   BOGARDUS 


was  misplaced  as  represented  by  the  dotted  line  /,  the  circuits 
represented  by  the  termini  b  and  b' ' ,  and  d  and  d'  were  closed 
respectively  and  two  errors  were  recorded  on  the  smoked  paper 


FIG.  i 


by  corresponding  markers.  It  was  not  possible  to  close  more 
than  two  circuits  and  hence  make  more  than  two  errors  by  a 
single  misplacement.  It  will  be  noted  that  the  inner  lines  of  a' 


32  RELATION  OF  FATIGUE   TO   INDUSTRIAL  ACCIDENTS 

and  df,  and  of  b'  and  c'  are  separated  by  one  and  three-eighths 
inches,  respectively,  so  that  a  leeway  of  three-eighths  of  an  inch 
in  either  direction  was  given. 

A  revolving  pulley  O  (Fig.  i),  driven  by  power  obtained 
through  a  speed-reducer  from  a  motor,  carried  a  double  arm,  m 
and  m1 '.  Both  m  and  mr  carried  shields  s  and  s't  respectively, 
set  at  an  angle  such  that  when  the  pulley  revolved,  the  blocks 
being  set  on  the  square  would  be  brushed  off  to  the  left  and 
toward  the  subject  who  was  seated  facing  x.  Each  of  the 
shields  s  and  s'  were  of  brass  (as  were  the  arms  m  and  m'  and 
the  pulley)  and  each  carried  a  small  brush  of  fine  brass  wire 
attached  to  the  lower  inner  corner.  As  the  shield  brushed  off  a 
block  at  x  the  small  wire  brush  passed  over  a  brass  knob  k  and 
closed  an  electrical  circuit,  which  occurrence  was  recorded  by  a 
fifth  marker  on  the  smoked  paper  mentioned  in  the  preceding 
paragraph.  Reference  to  the  smoked  paper  showed  the  nature 
of  errors,  i.e.,  the  direction  in  which  the  misplacement  occurred, 
the  number  of  errors,  and  their  occurrence  in  relation  to  the 
time-element.  An  observation  method  was  devised  which  served 
as  a  check  on  the  record  carried  by  the  smoked  paper.  Because 
of  a  great  variety  of  phenomena  which  happened  in  connection 
with  the  placement  of  the  blocks  and  which  the  registering 
apparatus  could  not  be  made  to  record,  the  observation  method 
proved  more  accurate  and  satisfactory  and  was  finally  adopted. 

Before  each  test  the  subject  was  given  as  much  time  as  he 
wished  for  practice.  He  did  not  know  exactly  when  his  test- 
period  began  nor  when  it  was  likely  to  close — except  that  he 
knew  that  it  would  not  extend  over  twenty  minutes.  By  this 
method  the  factors  of  "warming  up,"  of  the  nervousness  fre- 
quently attendant  on  beginning  a  piece  of  work,  and  of  the  "final 
spurt"  were  almost  entirely  eliminated.  The  actual  test-period 
was  made  fifteen  minutes  long  in  all  cases,  although  none  of  the 
subjects  knew  this  fact — fifteen  minutes  being  the  length  of  time 
determined  upon  as  sufficient  to  indicate  many  of  the  character- 
istics of  fatigue,  to  show  the  tendency  of  these  characteristics, 
and  to  bring  out  important  points  regarding  the  nature  of  mus- 
cular inaccuracies.  The  tests  were  made  on  successive  days  and 


EMORY  S.   BOGARDUS  33 

at  the  same  hour  each  day  for  the  given  subject  as  far  as  possible; 
any  variations  were  noted.  A  record  of  the  subject's  general 
physical  condition  at  the  beginning  of  each  test  was  kept  and 
also  of  the  subject's  introspections  at  the  close  of  the  daily  trial. 

The  following  method  of  evaluation  of  errors  was  adopted  as 
being  the  most  satisfactory.  If  the  block  was  misplaced  to  the 
left,  for  example,  so  as  to  establish  the  connection  represented 
by  the  termini  aar  (illustrated  by  the  dotted  square  r,  Fig.  2), 
one  error  was  counted ;  if,  as  shown  by  the  dotted  square  /,  the 
block  was  misplaced  so  as  to  make  the  connections  bb'  and  ddr, 
two  errors  were  recorded.  If  either  hand  of  the  subject  was  hit 
by  the  revolving  shields  s  and  s'f  three  errors  were  counted — 
such  an  occurrence  being  a  gross  inaccuracy.  Failure  to  put  in 
a  block — being  the  omission  of  a  whole  muscular  co-ordination — 
was  evaluated  at  five  errors.  Other  types  of  maladjustments 
occurred  occasionally  and  were  evaluated  on  the  above  basis. 

It  may  be  well  to  note  that  in  these  experiments  an  essential 
feature  of  the  method  is  that  stimuli  were  provided  of  the  so- 
called  extrinsic  nature.4  The  machine  being  driven  by  electricity 
set  the  pace  and  the  subject  was  required  to  keep  up.  To  the 
observer  these  tests  appeared  as  a  real  contest  between  human 
muscle  and  sensitive  nerves,  and  the  machine,  insensible  and  inde- 
fatigable. The  machine  regularly  worked  on  and  on;  the  subject 
worked  irregularly,  with  increasing  tendency  to  fall  behind. 

Although  in  these  experiments  no  saws,  knives,  or  drills  were 
present  and  hence  gross  muscular  inaccuracies  did  not  mean 
actual  mutilation  of  the  subject's  hands,  this  fact  appeared  to  be 
adequately  balanced  by  three  other  factors,  (a)  Throughout  the 
experiments  each  subject  clearly  manifested  an  instinctive  dread 
of  getting  hit  by  the  revolving  shield — even  in  the  final  experi- 
ments, the  subject  would  instinctively  jerk  back  his  hand  when- 
ever he  became  conscious  that  his  hand  was  likely  to  be  hit.  (&) 
Throughout  the  experiments  the  records  of  each  subject  were 
posted  and  a  healthy  spirit  of  competition  was  maintained  which 
assisted  greatly  in  keeping  up  a  maximum  efficiency,  (c)  In 
particular,  the  graduated  system  of  evaluating  inaccurate  co- 
ordinations served  continually  in  keeping  down  the  number  of 

4  W.  H.  R.  Rivers,  The  Influence  of  Alcohol,  etc.,  on  Fatigue,  12. 


34  RELATION  OF  FATIGUE   TO  INDUSTRIAL  ACCIDENTS 

gross  inaccuracies.  The  writer  believes  that  these  factors  when 
taken  together  served  to  maintain  a  degree  of  carefulness  in 
operating  this  experimental  machine  comparable  to  that  mani- 
fested by  the  average  worker  in  the  dangerous  trades,  who  in- 
evitably becomes  inured  to  the  danger  of  working  close  to 
revolving  knives,  saws,  drills,  etc. 

Eleven  subjects  participated  in  these  experiments.5  Br.,  Hy., 
Pr.,  Sp.,  Sw.,  and  Wr.  were  men;  Ch.,  Fr.,  Hys.,  My.,  and  Wd. 
were  women.  This  list  included  trained  psychologists  who  had 
worked  at  reaction-time  experiments,  at  co-ordination  of  hand 
and  eye  movements,  at  general  fatigue  experiments.  Three  of 
the  subjects  had  taken  part  in  the  prolonged  series  of  fatigue 
experiments  conducted  by  Yoakum.  One  of  the  subjects  had 
worked  in  a  screw  room;  another,  as  an  operator  in  a  telephone 
exchange.  In  view  of  the  considerable  amount  of  practice  which 
was  given  in  these  experiments  the  results  did  not  show  any 
particular  effects  of  the  previous  training  of  the  subjects.  This 
point  will  be  discussed  later.  Further  details  regarding  methods 
will  be  given  when  the  various  groups  of  experiments  are  de- 
scribed. 

The  first  group  of  experiments  was  designed  to  get  a  maxi- 
mum of  simplicity  of  operation,  of  monotony,  of  speed,  and  of 
mental  strain  or  unrelaxed  tension.  The  rate  was  such  as  to 
require  that  a  block  be  set  on  the  square  x  (Figs,  i  and  2)  once 
a  second  or  sixty  times  per  minute.  Two  blocks  were  used.  The 
cycle  of  a  single  operation  may  be  described  as  follows :  (a) 
stopping  block  i  with  the  left  hand  when  brushed  off  the  square 
x  by  the  machine,  and  putting  block  2  on  the  square  x  with  the 
right  hand;  (b)  passing  block  i  over  from  the  left  hand  to  the 
right  hand;  (c)  placing  block  i  on  the  square  with  the  right  hand 
while  the  left  hand  stopped  block  2 ;  and  so  on.  The  monotony, 
speed,  and  unrelaxed  tension  of  this  process  is  obvious. 

Eight  subjectsi — four  men,  Hy.,  Pr.,  Sp.,  Sw.,  and  four 
women,  Ch.,  Fr.,  Hys.,  and  Wd. — worked  in  Group  I.  Each 
subject  was  given  several  practice  trials,  covering  two  or  three 
weeks,  until  the  maximum  efficiency  was  obtained,  as  far  as  could 

*  The  writer  wishes  to  express  his  deep  obligation  to  the  persons  who  willingly  gave  of  their 
time  and  strength  that  this  investigation  might  be  furthered. 


EMORY   S.   BOGARDUS 


35 


be  judged  by  the  daily  records  of  errors.  The  tests  were  then 
continued  until  six  to  ten  normal  records  were  obtained  for  each 
subject.  By  the  use  of  volitional  power  and  highly  concentrated 
attention,  and  as  a  result  of  a  strong  spirit  of  rivalry,  the  subject 
tried  in  each  test  to  make  no  errors  or  to  keep  the  errors  within 
minimum  limits. 

Among  other  things,  the  errors  of  each  subject  were  tabulated 
according  to  their  occurrence  in  the  first  or  in  the  second  half 
of  the  given  test  periods.6  The  tabulated  figures  for  each  sub- 
ject were  added  together  and  the  average  daily  number  of  errors 
for  the  first  and  second  halves  of  the  test  periods  was  obtained. 
The  results  appear  in  Table  II. 

TABLE  II 
MUSCULAR  INACCURACIES  (GROUP  I) 


Subject 

Average  Num- 
ber of  Errors, 
First  Half 

Average  Num- 
ber of  Errors, 
Second  Half 

Average  Total 
Number  of 
Errors 

Ch.  . 

3.OO 

6  oo 

Q.OO 

Fr  

6.16 

iq.Si 

21  .00 

Hy  

6.66 

12.  OO 

18.66 

Hys  
Pr  

S.i6 

2  .OO 

13.00 
5.83 

18.16 
7.83 

Sp.  . 

4.  <;o 

5.83 

10.  w 

Sw.. 

1.83 

4.OO 

5.83 

Wd  

1.66 

3.83 

c  .40 

Total  

30-97 

66.32 

97.29 

General  average  .  .  . 

3-87 

8.29 

12.  16 

From  Table  II  it  will  be  observed  that  the  average  daily  num- 
ber of  errors  for  all  subjects  was  3.87  for  the  first  half  of  the 
test  periods  and  8.29  for  the  second  half.  In  other  words,  31.82 
per  cent  of  the  errors  occurred  in  the  first  half  of  the  test  periods 
and  68.17  per  cent  in  the  last  half.  As  determined  by  the  intro- 
spections, the  immediate  cause  of  the  distribution  of  muscular 
inaccuracies  in  this  fashion  is  to  be  found  largely  in  the  irregu- 
larly decreasing  effectiveness  of  the  attentive  processes.  In  par- 

6  In  analyzing  the  results  of  these  experiments,  a  large  number  of  tables  have  been  made. 
Only  those  have  been  selected  for  use  here  which  best  present  the  general  results.  It  is  difficult 
to  avoid  the  omission  of  some  classifications  of  data  which  might  prove  helpful. 


36  RELATION   OF  FATIGUE   TO   INDUSTRIAL  ACCIDENTS 

ticular,  such  factors  entered  as  rise  of  feelings  of  effort,  of 
strains,  of  fatigue  in  the  muscles  of  the  eyes,  arms,  back,  hands, 
legs,  abdomen,  etc.  In  many  of  the  tests  the  subjects  experienced 
a  growing  uncertainty  of  muscular  control  over  the  hands. 

Whatever  the  cause,  the  most  significant  result  of  this  group 
of  experiments  was  the  fact  that  the  subjects  were  not  able  to 
maintain  a  steady  degree  of  volitional  attention  even  though  they 
knew  that  the  test  would  cover  a  short  period  of  not  over  twenty 
minutes.  During  these  tests  the  subjective  processes  broke  down, 
in  spite  of  continued  efforts  of  the  subjects  to  the  contrary,  to 
the  extent  of  permitting  practically  twice  as  many  errors  to  occur 
in  the  second  half  as  in  the  first  half  of  the  work  period.  Some 
of  the  subjects,  whose  work  in  this  group  of  experiments  is 
fairly  typical,  are  working  for  much  longer  test  periods.  The 
strain  on  the  individual  caused  by  the  greater  length  of  the  work 
period  is  compensated  by  giving  him  a  slower  rate  of  speed. 
While  full  results  are  not  yet  at  hand,  the  indications  are  that 
when  the  longer  period  is  divided  into  two  equal  periods  for 
purposes  of  comparisons,  the  relation  between  the  number  of 
errors  occurring  during  the  first  half  and  during  the  second  half 
of  such  a  period  is  almost  a  duplicate  of  the  results  shown  in 
Table  II.  In  other  words,  when  the  operation  of  the  experi- 
mental machine  is  made  less  rigorous  and  continued  for  greater 
lengths  of  time,  so  that  fatigue  does  not  develop  in  fifteen 
minutes  (as  in  the  experiments  already  described),  but  in  the 
given  increased  period  of  time,  it  may  be  assumed  that  the  results 
in  Table  II  would  not  suffer  material  change. 

Tables  II  and  III  illustrate  the  law  of  fatigue  as  given  at  the 
close  of  Section  II,  that  continued  work  is  accompanied  by  in- 
creasing muscular  inaccuracy.  Granted  that  the  general  results 
of  this  group  of  experiments  would  not  have  been  essentially 
changed  if  a  lower  rate  of  speed  had  been  substituted  for  a  high 
rate  and  a  longer  period  of  time  substituted  for  a  short  period- 
two  substitutions  which  may  be  considered  as  counterbalancing 
each  other  in  a  large  measure — then  the  following  conclusion 
may  be  given:  If  the  subjects  in  this  series  of  experiments  had 
been  operating  dangerous  machines  where  slight  misplacements 


EMORY   S.   BOGARDUS  37 

mean  mutilation,  the  danger  of  accidents  would  have  been  far 
greater  (if  not  twice  as  great)  in  the  latter  half  than  in  the  first 
half  of  a  given  work  period. 

In  Section  II  the  point  was  emphasized  that  the  increase  in 
muscular  inaccuracy  which  accompanies  continued  work  depends 
on  the  rate  of  work.  That  is  to  say,  if  the  operative  of  a  dan- 
gerous machine  should  be  "speeded  up,"  his  danger  of  suffering 
accident  would  be  thereby  increased;  and  that  increased  danger 
would  persist  as  long  as  the  increase  in  rate  of  work  remained  a 
"speeded-up"  operation  for  the  given  operative.  According  to 
the  law  given  at  the  close  of  Section  II,  an  increase  in  speed  will 
hasten  the  fatigue  processes,  the  development  of  muscular  v;nac- 
curacies,  and  hence  the  chances  of  accident. 

In  testing  this  point  the  apparatus  used  in  the  preceding  series 
was  slightly  modified.  A  pipe  p  and  a  square  box  q  containing 
a  dozen  inch  cubes  were  added  to  the  apparatus  ( see  Fig.  i ) .  By 
this  time  the  observation  method  had  been  so  satisfactorily  de- 
veloped that  the  brass  plates  on  one  side  of  the  blocks  were  taken 
off  and  the  subject  permitted  to  place  the  blocks  with  any  side 
down.  The  cycle  of  operations  consisted  in  catching  the  block 
with  the  left  hand  as  it  was  brushed  off  the  square  x  by  the 
machine  and  of  dropping  it  in  the  opening  of  the  spout  p.  In 
the  mean  time  the  right  hand  had  to  pick  out  another  of  the 
blocks  from  box  q  and  place  it  accurately  on  the  square  x. 

The  speed  was  made  one-half  that  of  the  preceding  series,  or 
30  blocks  per  minute.  This  was  a  rate  which  seemed  slow  or 
moderate  to  most  of  the  subjects  and  errors  appeared  to  occur 
more  as  a  result  of  chance  than  from  any  other  cause.  As  far 
as  the  speed  was  concerned,  there  was  no  excuse  for  errors. 
Tests  were  made  daily  at  this  rate  until  a  series  of  records  was 
secured  sufficient  to  serve  as  a  basis  of  comparison  with  the 
results  obtained  from  speeding  up.  Then  the  rate  was  increased 
from  30  to  37^  blocks  per  minute.  On  the  day  that  test  i  was 
made  at  the  faster  rate,  and  preceding  the  test,  the  subject  was 
given  all  the  time  that  he  wished  for  practice.  Tests  at  the  37J4 
rate  were  continued  for  twelve  days  for  all  subjects.  Then  a 
faster  rate  of  45  blocks  per  minute  was  offered.  Table  III  gives 


RELATION  OF  FATIGUE   TO  INDUSTRIAL  ACCIDENTS 


the  number  of  errors  made  by  each  subject  during  the  series  of 
trials  at  the  three  rates  of  speed. 


TABLE  III 

MUSCULAR  INACCURACIES  (GROUP  II) 


Rate 

No.  of 
Trials 

Br. 

Fr. 

Hy. 

Hys. 

My. 

Pr. 

Wd. 

Wr. 

Total 

I 

I 

2 

2 

4 

4 

o 

6 

16 

35 

30  

2 

I 

6 

8 

2 

5 

i 

0 

4 

27 

3 

2 

3 

o 

O 

o 

12 

6 

9 

32 

4 

O 

i 

6 

I 

3 

2 

i 

i 

15 

i 

25 

92 

39 

127 

14 

39 

2 

44 

387 

2 

17 

57 

IS 

31 

IO 

54 

3 

23 

212 

3 

21 

15 

13 

18 

16 

15 

7 

39 

144 

4 

IO 

5 

29 

61 

14 

7 

3 

38 

l67 

5 

9 

6 

18 

5 

IO 

44 

3 

26 

117 

6 

9 

23 

3 

20 

ii 

23 

i 

18 

1x8 

37^  < 

7 

4 

12 

4 

i 

2 

7 

7 

14 

51 

8 

3 

29 

2 

4 

7 

17 

3 

6 

81 

9 

3 

23 

I 

3i 

4 

34 

i 

6 

103 

10 

3 

I 

7 

6 

i 

2 

6 

7 

33 

ii 

3 

22 

22 

4 

o 

8 

7 

4 

70 

12 

o 

9 

7 

7 

o 

7 

7 

33 

70 

I 

48 

128 

52 

148 

65 

"5 

70 

325 

943 

2 

101 

108 

18 

166 

56 

134 

56 

88 

736 

4.C,  . 

123 

117 

•22 

7i 

•2  A 

IO4. 

64 

202 

7^1 

4 

*•« 

57 

*  *  / 

182 

o^ 
75 

/  o 
21 

OT- 

*3 

xwif. 

102 

V*T 

26 

108 

/  o 

584 

5 

46 

79 

82 

134 

15 

118 

16 

256 

746 

Although  the  first  trials  at  the  37^  rate  in  the  case  of  each 
subject  were  preceded  by  a  practice  period,  the  effect  of  speeding 
up  from  a  30  to  a  37^  rate  on  muscular  inaccuracy  is  marked. 
As  indicated  by  Table  III,  the  increase  varies  considerably  from 
the  case  of  Wd.  to  that  of  Hys.,  where  the  increase  in  number  of 
inaccuracies  is  from  i  to  127.  For  the  first  six  trials  at  the  37 J4 
rate  the  process  was  clearly  a  speeded-up  one  for  all  the  subjects 
excepting  Wd. ;  a  decrease  in  errors  is  also  characteristic.  For 
the  last  six  trials  at  the  37^  rate,  the  totals  of  errors  indicate 
that  no  further  decrease  in  inaccuracies  would  have  resulted  if 
the  series  at  this  rate  had  been  continued.  The  introspections 
given  by  the  subjects  bear  out  this  conclusion.  The  totals  for 
these  last  six  trials  also  indicate  that  the  37^2  rate  had  become 
a  much  less  speeded-up  process  than  for  the  first  six  trials  at 


EMORY   S.   BOGARDUS 


39 


that  rate,  but  that  it  still  remained  a  speeded-up  process  when 
compared  with  the  records  for  the  30  rate. 

Table  III  shows  that  the  introduction  of  the  45  rate  (al- 
though the  first  trials  were  again  preceded  by  a  practice  period) 
was  accompanied  by  a  large  increase  in  the  number  of  errors. 
Table  IV  is  prepared  from  Table  III  and  indicates  the  relative 
percentage  of  errors  occurring  in  the  first  and  second  half  of  the 
trials  at  the  30  rate,  for  the  first  six  and  for  the  second  six  trials 
at  the  37J4  rate,  and  for  the  45  rate,  for  each  subject;  at  the 
30  or  slow  rate  where  errors  were  not  due  to  speed,  but  appar- 
ently to  chance,  the  average  percentages  of  errors  indicate  that 
practically  the  same  number  of  inaccuracies  occurred  in  the  first 
half  as  in  the  second  half  of  the  given  work  period — the  ratio 
being  50.0  to  49.8. 

But  when  the  rate  was  increased  to  37^  blocks  per  minute 
there  occurred  not  only  a  large  increase  in  the  actual  number  of 
errors,  but,  as  will  be  seen  by  looking  at  Table  IV,  a  large  pro- 

TABLE  IV 
PERCENTAGE  OF  ERRORS  (FROM  TABLE  III) 


SUBJECT 

30  RATE 

37*  RATE 
(FIRST  Six  TRIALS) 

37*  RATE 

(SECOND  Six 
TRIALS) 

4SRATE 

First 
Half 

Second 
Half 

First 
Half 

Second 
Half 

First 
Half 

Second 
Half 

First 
Half 

Second 
Half 

Br.. 

75-0 
33.3 
50.0 
25.0 
66.6 
73-3 
30.7 
46.6 

25.0 
66.6 
50.0 
75.0 
33-3 
26.6 
69.2 
53-3 

49-4 
49-4 
37-6 
42.3 
24.0 
19.1 
26.3 
3i-5 

SO.S 
62.8 
62.3 
57-6 
76.0 
80.8 
73.6 
68.4 

43-7 
32.0 
60.4 
39-6 
35-7 
4L3 
29.0 

50-7 

56.2 
67.8 
39.5 
60.3 
64.2 
58.6 
70.9 
49.2 

33.6 
29.9 
38.4 
36.7 
44-5 
34.8 
26.9 
40.9 

66.3 
70.0 
6l.S 
63.2 
SS.4 
6S.I 
73-0 
59-0 

Fr  

Hy  

Hys  

My 

^"•y  
Pr. 

Wd 

Wr    . 

Average  

50.0 

49-8 

33-4 

66.5 

41-5 

58.3 

35.7 

64.2 

portion  of  the  inaccuracies  occurred  in  the  second  half  of  the 
given  trials.  The  ratio  of  errors  between  the  first  and  second 
halves  of  the  first  six  trials  at  the  37^  rate  was  33.4  to  66.5.  For 
the  second  six  trials  at  the  37K  rate  when  this  rate  no  longer  in- 
volved as  speeded-up  operations  as  during  the  first  six  tests, 
because  of  skill  resulting  from  practice,  the  percentage  of  inac- 


40  RELATION  OF  FATIGUE   TO   INDUSTRIAL  ACCIDENTS 

curacies  fell,  the  ratio  being  41.5  to  58.8.  When  the  rate  was 
increased  to  45  blocks  per  minute,  the  process  again  became  a 
speeded-up  one  and  the  percentage  of  inaccuracies  in  the  last 
half  of  the  trial  periods  again  rose — this  time  to  64.2  per  cent. 
The  ratio  was  35.7  to  64.2. 

The  noteworthy  fact  in  these  experiments  is  that  as  soon  as 
the  work  was  speeded  up  from  the  30  to  the  37^  rate  or  from 
the  37^2  to  the  45  rate,  the  larger  part  of  the  increase  of  errors 
took  place  in  the  latter  half  of  the  given  work  periods.  These  in- 
creases clearly  show  the  effect  of  fatigue  on  muscular  inaccu- 
racies. This  conclusion,  based  on  the  objective  records,  is  corrobo- 
rated by  the  introspections  given  by  the  subjects.  While  operat- 
ing the  machine  at  the  speeded-up  rates,  all  the  subjects  com- 
plained of  sensations  of  fatigue  during  the  second  half  of  the 
work  periods,  ranging  from  distinct  strains  in  the  muscles  of  the 
eyes,  arms,  and  hands  to  temporary  paralysis  of  the  right  arm 
(Wr.,  in  whose  case  the  right  arm  co-ordinations  broke  down 
completely,  and  the  subject  was  forced  to  stop  in  one  test) .  Typi- 
cal introspective  reports  are  subjoined : 

Eye  strain  felt  during  last  three  or  four  minutes. 

Slammed  blocks  in  toward  close  of  period,  because  of  less  certainty  of 
muscle  control. 

During  last  half  of  period  eyes  blurred  continually. 

Back  began  to  ache  about  middle  of  period  and  continued. 

Conscious  of  increasing  inaccuracy  and  of  increasing  feeling  of  "losing 
out." 

Greater  tendency  toward  the  last  to  fumble  blocks. 

Fumbling  increased,  caused  by  developing  fatigue  in  fore-arm,  and  by 
lapses  of  attention. 

Fatigue  in  arms  felt  early  in  trial. 

Fagged  all  over — to  keep  up  the  process  became  a  torture. 

Felt  pain  between  shoulders  toward  the  last. 

Almost  decided  that  I  couldn't  keep  it  up  for  full  period. 

Compelled  to  exert  increasing  volitional  power. 

Strain  in  left  arm  toward  the  end  of  the  period. 

Increasingly  tended  to  get  behind  in  muscular  movements. 

Boredom  of  it  increased. 

Last  few  minutes  seemed  like  hours. 

Started  well,  but  fatigue  developed  in  arms,  wrists,  shoulders. 

Terrible  strain  developed  in  right  arm. 

Became  aware  of  a  general  inaccurate  feelincc  in  regard  to  hands. 


EMORY   S.   BOGARDUS  41 

One  or  two  other  points  brought  out  by  this  group  of  ex- 
periments may  be  mentioned  here.  Reference  to  the  tables  will 
make  clear  the  fact  of  marked  individual  difference  in  regard  to 
making  errors.  These  variations  do  not  appear  to  be  explained 
when  the  subjects  are  classified  on  the  men  and  women  basis  or 
according  to  the  degree  of  psychological  training,  but  rather 
by  temperamental  differences.  Reference  to  the  records  of  indi- 
vidual subjects  (Table  III)  shows  marked  variations  from  day 
to  day  in  many  cases.  The  explanation  for  this  fact  appears  to 
be  found  in  the  varying  bodily  conditions  of  the  given  subject 
from  day  to  day.  The  decidedly  abnormal  conditions  were  of 
two  kinds — either  the  subject  found  himself  simply  "out  of 
form,"  or  else  he  began  the  test  normally  and  errors  began  to 
increase  early  and  rapidly  as  a  result  of  late  hours,  overwork, 
forms  of  illness. 

The  material  presented  in  this  section  may  be  summarized  at 
this  point.  These  experiments  indicate  that  uninterrupted  work  is 
accompanied  by  increasing  muscular  inaccuracy,  and  other  things 
being  equal,  any  speeding  up  in  the  operation  of  dangerous  ma- 
chinery means  accelerated  development  of  fatigue  and  of  muscular 
inaccuracy.  In  other  words,  fatigue  causes  muscular  inaccuracy. 
Since,  as  indicated  in  Section  III  of  this  study,  men  and  women 
in  the  hazardous  employments  are  working  in  close  proximity 
to  dangerous  tools,  and  where  misplacement  of  the  hands  a  frac- 
tion of  an  inch  means  mutilation,  the  material  presented  in  this 
section  may  be  considered  as  evidence  that  fatigue  causes  acci- 
dents. The  data  presented  in  Section  III  to  the  effect  that  mus- 
cular inaccuracies  are  the  actual  phenomena  preceding  a  large 
majority  of  accidents  bears  out  the  conclusion  that  fatigue,  mus- 
cular inaccuracies,  and  industrial  accidents  are  causally  related. 
In  the  next  section,  the  hours  when  accidents  occur  will  be 
analyzed. 


RELATION   OF   FATIGUE   TO   INDUSTRIAL  ACCIDENTS 


V.    ACCIDENT-HOURS 

Reference  is  made  in  Section  III  to  a  study  of  accident 
records  (State  of  Illinois  for  the  year  1910)  which  has  been 
made  by  the  writer.  It  will  be  recalled  that  of  the  accident  re- 
ports examined,  2,687  gave  a  fairly  accurate  description  of  what 
happened  preceding  the  given  accidents;  and  2,203  or  &2-2  Per 
cent  of  the  2,687  accidents  conceivably  might  have  been  avoided 
if  the  injured  or  the  fellow-servant,  who  was  the  cause  of  the 
accident  in  some  cases,  had  had  accurate  muscular  control.  Of 
the  2,203  accidents  which  might  have  been  avoided,  the  time  at 
which  2,162  of  these  occurred  was  given.  These  reports  were 
tabulated  according  to  the  hours  of  the  day,  and  the  results 
appear  in  Table  V.  In  general,  there  is  ajise  in  the  number  of 
accidents  during  the  forenoon,  a  decided  fall  after  the  noon 
period  of  rest,  and  another  rise  in  the  afternoon  hours.  Further 
conclusions  must  be  withheld  until  certain  factors  are  considered. 
A  vital  point  is  to  be  found,  not  in  the  number  of  accidents  per 
hour,  but  in  the  number  of  accidents  per  hour  during  a  period 
when  the  same  number  of  employees  are  at  work. 

TABLE  V 

ACCIDENT-HOURS   (ILLINOIS,    IQIo) 


Morning 

Accidents 

Afternoon 

Accidents 

7  to    7  :  so   . 

7O 

I  to  I  '  SO 

ill 

8  to    8  :  so  .  . 

ISO 

2  to  2  '  SO 

is6 

9  to    o  :  <;o   . 

IQ2 

3  to  ^  *  so 

227 

10  to  10:59.  ... 

y2 
24.6 

4  to  4."  SO 

260 

1  1  to  1  1  :  59  

2S7 

s  to  s  •  so 

I4.S 

12  to  12:59.  ... 

4.Q 

o  «*»  o  •  ov  
Other  hours 

280 

The  figures  given  in  Table  V  represent  factories  in  which 
the  working  hours  are  not  similar.  While  in  general  the  working 
day  is  from  7  A.M.  to  6  P.M.  with  a  rest  period  from  12  M.  to  i 
P.M.  in  the  factories  to  which  the  statistics  in  Table  V  apply, 
there  are  important  variations.  In  many  factories  especially 
where  women  are  employed,  the  day  begins  at  7:30  A.M.  The 
time  of  the  lunch  period  at  noon  varies — in  one  plant  employing 


EMORY   S.   BOGARDUS  43 

about  3,000  men  and  women,  the  writer  found  that  practically 
one-half  of  this  number  take  their  lunch  period  from  n  130  to 
12.  Frequently  the  employees  begin  their  afternoon  period  of 
work  at  12  145  P.M.,  and  in  some  cities  at  12 130  P.M.  In  the  large 
cities  the  working  day  closes  in  a  considerable  number  of  cases 
at  5  130  P.M.  or  5  P.M.  ;  and  if  there  is  Saturday  afternoon  work, 
at  4  P.M.  A  study  of  the  work-hours  of  the  factories  to  which 
the  figures  in  Table  V  apply  shows  that  from  7  A.M.  to  8  A.M., 
from  ii  A.M.  to  i  P.M.,  and  after  5  P.M.  a  lesser  number  of  em- 
ployees are  at  work  than  during  the  other  work-hours,  when  the 
employees  of  all  the  factories  represented  are  considered  in  the 
aggregate.  If  the  table  shows  a  smaller  number  of  accidents 
during  the  hour  from  7  to  8  A.M.  than  in  the  succeeding  hour,  it 
is  not  safe  to  infer  that  the  danger  of  accident  is  correspondingly 
less,  since  a  smaller  number  of  persons  are  at  work  from  7  to  8 
A.M.  than  during  the  following  hour.  In  Table  V  the  periods 
from  8  to  1 1  A.M.  and  from  i  to  5  P.M.  are  of  almost  uniform 
employment. 

In  considering  this  period  of  uniform  employment  the  rate  \ 
of  work  must  be  taken  into  account  before  definite  conclusions 
may  be  drawn  regarding  the  influence  of  fatigue.     As  pointed   , 
out  in  Section  IV,  the  greater  the  speed  of  work,  the  greater  is 
the  danger  of  accident,  and  vice  versa.     Hence  the  question    \ 
arises :  Is  the  rate  of  work  uniform  in  connection  with  dangerous 
machinery  ? 

In  a  recent  investigation  by  the  United  States  Bureau  of 
Labor,  records  were  taken  from  hour  to  hour  from  stamping 
presses  equipped  with  automatic  counters  for  registering  the 
production.  Records  were  kept  for  twenty- three  machines  for 
periods  varying  from  one  day  to  seven.  With  reference  to  the 
results,  the  report  of  the  Bureau  of  Labor  says  that  it  is  ex- 
tremely probable  "that  there  is  an  average  slackening  of  activity 
on  the  part  of  the  workers  in  the  last  hour  and  a  half  of  the 
day."1  If  this  explanation  be  correct  and  be  applied  to  the  after- 

*  Quoted  from  proof-sheets  of  Vol.  XI  of  the  "Report  on  Condition  of  Woman  and  Child 
Wage-Earners  in  the  United  States,"  Senate  Doc.  No.  645,  6ist  Cong.,  2d  sess. 


44  RELATION   OF  FATIGUE   TO   INDUSTRIAL  ACCIDENTS 

noon  period  of  uniform  employment  from  i  to  5  P.M.,  it  will  be 
seen  that  the  last  hour  from  4  to  5  P.M.  is  probably  one  during 
which  the  rate  of  activity  is  much  less  than  during  the  preceding 
hours.  In  general  and  on  the  average  it  may  be  assumed  that 
the  afternoon  period  from  i  to  4  P.M.,  like  the  forenoon  period 
from  8  to  ii  A.M.,  is  one  of  both  uniform  employment  and  of 
fairly  uniform  rapidity  of  work. 

From  each  of  the  three-hour  periods  of  both  uniform  em- 
ployment and  rapidity  of  work  three  other  factors  have  been 
eliminated:  (a)  During  the  last  half -hour  of  work  before  noon 
and  before  the  time  for  closing  there  is  likely  to  occur  what  is 
called  the  "final  spurt,"  which  comes  with  the  realization  that 
one's  work  is  nearly  finished  and  which  tends  to  reduce  the  dan- 
ger of  accident  because  of  the  increased  volitional  forces  brought 
to  bear  upon  the  work,  (b)  The  close  of  the  working  period  is 
to  some  extent  a  period  of  readjustment — accumulated  work  is 
removed;  new  stock  is  secured  in  order  that  the  next  period  of 
activity  may  go  forward  unhindered.2  (c)  There  enters  also  the 
sense  of  accomplishment.  The  worker  may  proceed  more  lei- 
surely to  the  close  of  the  period,  after  he  has  accomplished  a  cer- 
tain amount  of  work  and  has  his  task  well  in  hand.3 

The  question  arises :  How  do  the  afternoon  totals  compare 
with  the  forenoon  totals  ?  But  an  adequate  basis  of  comparison 
is  not  present.  In  the  first  place,  the  forenoon  period  is  often 
longer  than  the  afternoon  period.  Further,  it  is  not  correct  to 
compare  the  totals  for  the  hours  from  i  to  4  P.M.  with  those  from 
8  to  ii  A.M.  because  the  existence  of  a  Saturday  half-holiday 
during  the  summer,  and  in  some  trades  throughout  the  year,  de- 
presses the  afternoon  totals,  while  a  high  number  of  accidents 
on  Monday  mornings  after  the  Sunday  holiday  unduly  increases 
the  forenoon  totals.  Also/ the  evidence  indicates  that  the  rapidity 
of  work  is  considerably  lessened  in  the  last  hour  and  a  half  of 
the  day's  work  and  the  chances  of  accident  are  correspondingly 
decreased. 

*  Op.  cit.,  Senate  Doc.  No.  645,  Vol.  I,  395- 
'Ibid. 


EMORY  S.   BOGARDUS 


45 


(^  Fig.  3  illustrates  Table  V  and  makes  graphic  the  more  or 
less  regular  increase  in  the  number  of  accidents  during  both  the 
forenoon  and  afternoon  periods  of  uniform  employment  and  of 
uniform  speed  of  activity.)  The  fall  in  the  number  of  accidents 
following  the  noon  period  of  rest  is  striking.  When  it  is  re- 
called that  Table  V  and  Fig.  3  apply  only  to  those  accidents 
(Class  B)  which  were  immediately  preceded  by  muscular  inac- 
curacies of  small  proportion  (see  Section  III),  further  illu- 
mination thus  will  be  given  to  the  law  of  fatigue  as  stated  at  the 


No.  of  a 
Accidents  — 
7  to    8  A.M. 

8  tO     Q  A.M. 
9   to  IO  A.M. 
10  tO  IX  A.M. 
XI  A.M.  tO  12  M. 

12  M.  tO  I  P.M. 
X    tO  2  P.M. 
2   tO  3  P.M. 
3  to  4  P.M. 
4  to  5  P.M. 
5  to  6  P.M. 
Other  hours 

ccidents  50                   xoo                 150                 200                 250                 300 

| 

I 

1 

| 

1 

|_ 

J 

I 

" 

FIG.  3 

close  of  Section  III;  namely,  that  (the  increasing  muscular  inac- 
curacy accompanying  uninterrupted  work  results  in  increasing 
numbers  of  accidents.) 

The  question  of  accident-hours  has  hardly  been  raised  as  yet 
in  the  United  States.  Only  a  few  states,  such  as  Wisconsin, 
Minnesota,  and  Illinois,  require  that  the  exact  time  of  accidents 
be  reported  to  the  offices  of  factory  inspection.  At  best,  sta- 
tistics of  accident-hours  in  the  United  States  are  unsatisfactory. 
Table  VI  is  prepared  frorn  the  accident  records  of  Wisconsin 
for  the  year  1 907-8.*  It  should  be  noted  that  in  Table  VI 
and  in  the  tables  of  accident-hours  which  follow  that  all  accidents 
are  included — those  due  to  the  breaking  of  machinery,  etc.; 
whereas  in  Table  V  (Illinois  statistics)  only  those  accidents  are 

4  Bur.  of  Labor  and  Industr.  Statis.  (Wis.),  itfh  Biennial  Report,  Part  I  (1007-8),  78. 


46 


RELATION  OF  FATIGUE   TO  INDUSTRIAL  ACCIDENTS 


classified  which  conceivably  might  have  been  avoided  if  the  in- 
jured parties  had  had  accurate  muscular  control.  The  question 
is  raised  by  the  compiler  of  the  Wisconsin  figures  why  the  largest 
number  of  accidents  did  not  occur  in  the  last  hour  of  work. 
Since  many  establishments  close  at  some  point  between  5  and  6 
P.M.  the  lessened  number  of  accidents  for  this  hour  may  be  ac- 
counted for  in  this  way  in  large  measure.  The  explanation  for 
the  relative  decrease  in  the  number  of  accidents  from  n  to  12 
P.M.  may  be  threefold:  (a)  As  in  Illinois,  there  may  be  whole 
shifts  of  men  and  women  who  take  their  lunch  period  at  1 1 130 
A.M.,  and  hence  are  not  working  during  the  last  half -hour;  (b) 
There  presumably  is  a  slackening  of  the  rate  of  work  with  a 
correlative  decrease  in  danger  of  accident;  (c)  Some  workmen 
with  a  surplus  of  energy  may  experience  the  "final  spurt"  and 
thus  the  danger  of  accident  may  be  lessened. 

TABLE  VI 

ACCIDENT-HOURS   (WISCONSIN,   1907-8) 


Morning 

Accidents 

Afternoon 

Accidents 

7  to     7  *  "sO 

156 

i  to  i  :  <\o  .  . 

247 

8  to    8  •  59 

2/14 

2  to  2  :  so  .  . 

4O7 

9  to    o  '  ^o 

4.27 

•2  to  3  :  so  .  . 

4-zc 

10  to  10*  59 

486 

4  to  4:  <o  .  . 

446 

1  1  to  1  1  '  59              .  . 

376 

5  to  s  :  so  .  . 

277 

At  all  events,  a  consideration  of  the  Wisconsin  statistics  for 
the  hours  of  uniform  employment  and  uniform  rapidity  from  8 
to  ii  A.M.  and  from  i  to  4  P.M.  would  eliminate  many  extrane- 
ous elements  and  justify  the  conclusion,  as  in  the  case  of  the 
Illinois  statistics,  that  fatigue  is  a  causal  factor  in  accidents. 

Table  VII  shows  the  distribution  of  accidents  through  the 
day  in  New  England  and  southern  cotton  mills.5  The  table  in- 
cludes figures  from  three  series. 

Of  the  three  series  presented,  that  of  accidents  in  one  New  England 
mill  for  an  eight-year  period  is  the  most  significant,  since  it  shows  the 
comparatively  unhindered  operation  of  uniform  causes.  In  this  series  the 
percentage  of  accidents  gradually  rises  during  the  forenoon  until  n  o'clock, 

*  Op.  cit.,  Senate  Doc.  No.  645,  Vol.  I,  395. 


EMORY  S.   BOGARDUS 


47 


and  then  there  is  a  decided  drop.  In  the  afternoon  the  percentage  remains 
comparatively  low  until  4  o'clock,  when  there  is  a  considerable  rise  followed 

by  a  large  decrease  in  the  percentage  during  the  last  hour  of  the  day 

The  accident  distribution  is  apparently  a  product  of  at  least  two  factors. 
The  worker  in  beginning  gradually  increases  his  speed,  the  result  being  a 
combination  of  increasing  speed  with  growing  fatigue.  A  basis  is  thus 
furnished  for  a  growing  accident  rate.  As  already  indicated,  there  is  an 
increase  in  percentage  of  accidents  both  in  morning  and  afternoon;  but  in 
the  latter  period  the  process  is  not  repeated  on  the  same  scale  as  during  the 
morning  hours.  The  drop  at  the  end  of  the  period  has  several  factors  whirh 
vary  from  industry  to  industry.  The  fatigue  is  itself  a  large  element  in  the 
result.  It  finally  overcomes  to  a  degree  the  driving  energy  which  has  kept 
up  the  speed.8 

TABLE  VII 

ACCIDENT-HOURS   (iN  COTTON  MlLLS) 


Morning 

Accidents 

Afternoon 

Accidents 

7:01  to    8  

163 

i  :oi  to  2  

14.1 

8  *  01  to    o 

208 

2  "  OI  to  3 

i6« 

O'OI  to  IO 

2CJI 

3'OI  to  d 

IQ'l 

lO'OI  to  II 

242 

4*01  to  ^ 

14.7 

II  *OI  tO  12 

121 

5  'oi  to  6 

O2 

In  presenting  tables  of  accident-hours  compiled  from  the 
records  of  nineteen  establishments  engaged  in  metal  manufacture 
(a  special  inquiry  made  by  the  United  States  Department  of 
Labor)  and  from  the  unpublished  records  of  the  Indiana  depart- 
ment of  factory  inspection  for  two  years,  the  Bureau  of  Labor 
says,  by  way  of  analysis  of  the  figures : 

It  is  evident  that  in  the  inter-relation  of  influences  acting  upon  the  situa- 
tion now  one  and  now  another  may  be  dominant.  The  most  constant  factor 
will  be  fatigue.  It  will  be  present  in  varying  proportion  in  every  case.  It 
may  act  with  the  tendency  to  increase  speed  and  thus  to  produce  a  greater 
number  of  accidents.  It  may  in  the  end  become  so  pronounced  that  speed 
is  reduced  and  the  accident  rate  lowered.  (It  should  not  be  forgotten,  how- 
ever, that  this  lowered  accident  rate  is  presumably  far  higher  than  it  would 
be  were  the  laborer  working  at  this  reduced  rate  while  yet  unfatigued.) 

There  will  be  some  tendency  to  minimize  the  factor  of  fatigue  in  the 
above  process,  because  it  is  not  a  matter  of  acute  sensation.  It  gradually 
upsets  those  nice  adjustments  of  the  living  organism  upon  which  depend 
efficient  labor  and  the  safety  of  the  worker Reduce  the  alertness  and 

6  Ibid. 


48  RELATION  OF  FATIGUE   TO  INDUSTRIAL  ACCIDENTS 

the  exactness  with  which  the  body  responds  to  the  necessities  of  its  labor, 
and  by  just  so  much  have  you  increased  the  liability  that  the  hand  will  be 
misplaced  that  fraction  of  an  inch  which  means  mutilation. 

The  law  of  fatigue  is  a  universal  law.    We  may  change  its  operation,  but 

cannot  eliminate  the  fact The  weaker  organism  suffers  soonest  and 

most.1 

It  may  be  well  to  note  here  the  two  methods  of  tabulating 
accidents  according  to  hours.  The  unsatisfactoriness  of  both 
methods  is  due  to  the  fact  that  accidents  occurring  from  one  to 
fifteen  minutes  before  or  after  a  given  hour,  say  8  A.M.,  are 
frequently  reported  as  occurring  at  8  A.M.  In  Table  VII, 
accidents  are  tabulated  from  7:01  to  8  A.M.,  etc.,  and  accidents 
which  really  happen  after  eight  o'clock  and  belong  to  the  second 
hour  are  included  in  the  record  for  the  first  hour  of  work.  Thus 
to  each  hour-period  of  the  day  many  accidents  are  accredited 
which  really  belong  to  the  succeeding  hour.  Ten  to  eleven  A.M. 
in  Table  VII,  for  instance,  really  means  10:15  to  n  115  A.M.  or 
thereabouts,  and  the  greatest  number  of  accidents  really  occurred 
somewhat  later  in  both  the  forenoon  and  afternoon  periods  than 
is  indicated. 

On  the  other  hand,  in  Tables  V  and  VI  accidents  have  been 
tabulated  from  7  to  7.59  A.M.,  etc.  This  method  is  incorrect  in 
the  other  direction.  Some  accidents  occurring  shortly  before 
8  A.M.  and  in  the  first  hour  of  work  have  been  reported  as  oc- 
curring at  8  A.M.,  and  hence  are  included  in  the  record  for  the 
second-hour  period.  In  the  succeeding  ten  tables  both  methods 
have  been  used,  as  far  as  the  writer  can  determine.  On  the 
whole,  it  appears  that  the  inaccuracies  of  the  two  sets  of  errors 
to  a  certain  extent  counterbalance  each  other. 

The  Minnesota  Bureau  of  Labor  has  recently  published  a  table 
giving  a  classification  of  hours  of  the  accidents  which  were  re- 
ported to  the  Bureau  during  the  year  August  i,  1909,  to  July 
31,  1910.  In  commenting  on  this  table  the  Bureau  says:8 

Fatigue  and  nerve  strain  also  have  a  place  among  the  causes  of  acci- 
dents and  the  table  and  chart  below  (see  Report)  suggest  that  it  may  be  an 
important  place.  The  question  should  be  given  further  consideration. 

70p.  cit.,  Senate  Doc.  No.  645,  Vol.  I,  395- 

1  Bureau  of  Labor,  etc.  (Minn.),  izth  Biennial  Report  (1900-10),  137,  140. 


EMORY  S.   BOGARDUS 


49 


The  curves  seem  conclusive  that  ....  fatigue  largely  explains  the  lapse 
of  attention  that  causes  injury  in  the  later  portion  of  the  working  period 

In  the  study  of  accident-hours,  European  countries,  notably 
France  and  Germany,  are  far  ahead  of  the  United  States.  In 
France,  a  study  of  accident-hours  has  been  made  by  Professor  A. 
Imbert  of  the  University  of  Montpelier.  He  found  that  a  study 
of  5,534  accidents  distributed  among  140,407  workers  in  the 
cir  conscription  de  Toulouse  gave  results  similar  to  those  indi- 
cated by  Table  VIII.  These  statistics  apply  to  wood-workers, 
the  chemical  industries,  building  trades,  etc.  Table  VIII  refers 

TABLE  VIII 

ACCIDENT-HOURS   (FRANCE,   1904) 


Morning 

Accidents 

Afternoon 

Accidents 

7  to    8.    . 

232 

I  to  2  

132 

8  to    o 

7QI? 

2  tO  3 

•?io 

o  to  10 

•24.0 

7  to  4.. 

421 

10  to  ii 

O^ 
4?8 

4  to  "?. 

CI2, 

II  to  12 

202 

s  to  6.  .  . 

2(\4 

to  the  year  1904,  represents  all  industries,  and  covers  the  depart- 
ments of  Herault,  Aveyron,  Lozere,  Cantal,  and  Tarn.9  Imbert 
interprets  these  figures  as  follows : 

A  large  number  of  accidents  result  directly  from  the  physical  or  mental 
fatigue  of  the  workmen  at  the  moment  of  the  accident  and  this  assertion 

can  easily  be  proved  by  innumerable  instances One  result  ....  is 

that  fatigue  renders  the  workman  less  apt  to  avoid  accident  since  he  cannot 
make  ("ne  peut  plus  realiser")  as  intense  an  effort  as  usual  nor  execute 

movements  of  his  normal  rapidity Two  facts  are  shown  very  clearly 

by  this  table  of  figures  (see  Table  VIII)  ;  namely,  the  considerable  share 
played  by  fatigue  in  producing  accidents  and  the  equally  important  influence, 
in  the  inverse  sense,  of  the  midday  hour  of  rest.10 

Fatigue  being  the  inevitable  consequence  of  work,  accidents  inexorably 
increase  from  hour  to  hour.™ 

Imbert  refers  to  the  inquiries  made  by  M.  Le  Roy,  division 
factory  inspector  of  Toulouse,  for  the  years  1903  and  1904,  and 
says  that  the  results,  which  apply  to  several  thousands  of  acci- 

» A.  Imbert  and  M.  Mestre,  "Nouvelles  statistiques  d'accidents  du  travail,"  Rev.  Scien- 
tifique,  October  21,  1905,  521. 

10  A.  Imbert,  "Les  accidents  du  travail  et  les  compagnies  d'assurances,"  Rev.  Scientifique, 
June  4,  1904,  715. 

"  See  Footnote  7. 


RELATION  OF  FATIGUE  TO  INDUSTRIAL  ACCIDENTS 


dents,  are  in  harmony  with  his  results  ("toutes,  sans  exception, 
presentent  les  caracteres  generaux  que  nous  avons  enumere 
cidessus").  An  excerpt  from  M.  Le  Roy's  analysis  is  subjoined. 
It  is  indisputable,  in  fact,  that  the  more  fatigued  a  worker  is,  the  more 
liable  he  is  to  accident.  The  accident  is  then  the  consequence  of  the  com- 
bined results  of  physical  depression,  relaxed  attention,  and  less  rapid  move- 
ments  All  these  data  and  the  various  statistics  to  which  reference 

has  been  made  bring  us  necessarily  to  a  consideration  of  fatigue  as  one  of 

the  chief  causes  of  accidents This  cerebral  fatigue,  due  to  monotonous. 

speeded-up  labor,  induces  a  nervous  depression  which  is  betray^  Ky  inaf- 
tentiorvvery  often  resulting  in  accident  It  is  precisely  this  form  of  fatigue 
that  explains  the  increasing  progression  of  accidents  with  the  progress  of 
working  hours  in  industries  where  work  is  most  often  limited  to  watching 
machinery.13 

Germany  was  among  the  first  nations  to  require  that  accident- 
hours  be  reported.  Table  IX  is  compiled  from  the  German  acci- 
dent statistics  for  the  years  1887  and  1891,  and  applies  to  all  of 
the  various  trades  and  to  agriculture  combined.  The  accidents 
represented  in  Table  IX  appear  to  have  been  reported  with  more 
system  than  that  shown  in  the  reporting  of  accident-hours  in 
other  countries,  with  the  possible  exception  of  France.  Table 
IX  represents  a  wide  and  comprehensive  range  of  accidents.13 

TABLE  IX 

ACCIDENT-HOURS  (GERMANY,  1887,  1891) 


Morning 

Accidents 

Afternoon 

Accidents 

7  to  8 

IX4I 

I  to  2  

1,727 

8  to  9 

1.  06  1 

2  to  3  .  . 

2,44.  c 

9  to  10 

2,4-QO 

3  to  4..  . 

3,220 

10  to  ii 

•2  Ate 

4  to  ^  ,  . 

3,104 

II  to  12 

3,213 

S  to  6.  . 

2,824 

The  results  of  the  investigations  made  in  Germany  in  the 
years  1897  and  1907  are  similar  in  the  main  to  those  given  in 
Table  IX.14  Of  the  81,284  accident  cases  reported  for  the  year 

11  See  Brandeis  and  Goldmark,  Ten-Hour  Law  for  Women  (New  York),  241,  242. 

13  See  E.  R.  Krejcsi,  £•  Cong.  Intern.  d'Hyg.  et  de  Demog.,  VII,328;  also  the  24th  Annual 
Report,  Commissioner  of  Labor  (U.S.),  Vol.  I,  1132-34;    also  the  i?th  Annual  Report,  New 
York  Bureau  of  Labor  Statistics,  73°-939- 

14  See  Amtliche  Nachrichten  des  Reichs-Versicherungsamts,  Beiheft  I,  Teil  i  (1910);   also 
see  Bulletin  of  the  Bureau  of  Labor,  No.  92  (January,  1911).      It  should  be  noted  that  these 
German  statistics  refer  to  fatal  accidents  and  to  those  cases  where  the  injured  was  disabled 
for  more  than  thirteen  weeks.    They  include  the  accident  reports  from  the  mining,  quarrying, 
iron-and-steel,  metal-working,  textile,  wood-working  industries  and  from  the  building  trades. 


EMORY   S.   BOGARDUS 


1907,  13.87  per  cent  occurred  between  the  hours  of  6  and  9  A.M., 
and  28.42  per  cent  between  the  hours  of  9  A.M.  and  12  M.  ;  while 
13.81  per  cent  happened  between  the  hours  of  12  and  3  P.M.,  and 
26.32  per  cent  between  the  hours  of  3  and  6  P.M.  In  regard  to 
the  45,971  accident  cases  reported  for  the  year  1897,  the  per- 
centages of  the  accidents  for  the  different  sections  of  the  day 
run  approximately  parallel  with  those  given  for  the  year  1907. 
For  both  years  the  increase  in  the  number  of  accidents  during 
the  forenoon  and  afternoon  periods  is  most  pronounced  in  the 
metal-working  trades.  The  percentages  for  the  424  accident 
cases  reported  in  1907  for  the  South  German  metal-workers  were 
as  follows :  12.89  P61"  cent  f°r  the  hours  from  6  to  9  A.M.,  and 
37.23  per  cent  for  the  hours  from  9  A.M.  to  12  M.,  and  11.93  Per 
cent  for  the  hours  from  12  M.  to  3  P.M.,  and  32.22  per  cent  for 
the  hours  from  3  to  6  P.M. 

In  England  little  attention  has  been  given  to  accident-hours; 
a  partial  and  inadequate  list  of  accidents  in  factories  and  work- 
shops for  the  year  1903  may  be  found  in  the  British  Sessional 
Papers,  House  of  Lords.15  Table  X  gives  the  figures  of  a  recent 
study  of  accident-hours  in  Belgium  (1907)  and  applies  to  all 
industries.18 

TABLE  X 

ACCIDENT-HOURS   (BELGIUM,    1907). 


Morning 

Accidents 

Afternoon 

Accidents 

7  to    8 

roo 

I  to  2 

1*6 

8  to   o 

AC  A 

a  to  <  .  . 

4O^ 

9  to  10     

«;86 

3  to  4..  . 

787 

10  to  ii  

83  < 

4.  to  <  .  . 

<O4 

II  to  12  

675 

<;  to  6  .  . 

568 

In  Copenhagen,  Dr.  H.  Bille-Top  kept  a  record  for  ten  years 
(1898  to  1907)  of  the  industrial-accident  cases  which  he  was 
called  upon  to  attend — according  to  the  hour  of  their  occur- 
ence.17  Dr.  Bille-Top  attributes  the  increase  in  the  number  of 

"Vol.  LIX,  an. 

"  Ministere  de  1'industrie  et  du  travail,  Rapports  annuels  de  ^inspection  du  travail  (1907), 
ai2,  213. 

"  H.  Bille-Top,  "Die  Verteilung  der  Unglucksfalle  der  Arbeiten,  die  Wochentage  und  die 
Tagesstunden,"  Centralbl.  /.  Allegemein.  Gesundheitspfl.,  XXVII,  197. 


52  RELATION  OF  FATIGUE   TO  INDUSTRIAL  ACCIDENTS 

accidents  in  both  the  forenoon  and  afternoon  periods  to  increas- 
ing fatigue  ("zunehmender  Miidigkeit,  zunehmender  Abge- 
spanntheit"  ) . 

Professor  G.  Pieraccini  and  Dr.  R.  Maffei,  head  physicians 
in  the  Royal  Main  Hospital,  Florence,  have  made  an  investiga- 
tion of  the  accidents  (with  reference  to  accident-hours)  which 
took  place  in  some  of  the  railway  machine-shops  of  Italy  (1901 
to  1905).  The  results  of  their  tabulation  of  accident-hours  are 
given  in  Table  XI.  They  omit  the  first  hour  of  work  of  both 

TABLE  XI 

ACCIDENT-HOURS   (ITALY) 


Hours  of  Work 

Accidents 

2d  

206* 

*d.  . 

258 

4th.  . 

«3« 

•3.2  A^ 

5th.. 

32^ 

periods  of  the  day — because  fewer  workmen  are  at  work  than 
during  the  succeeding  hours.  The  accidents  for  the  correspond- 
ing hours  of  the  forenoon  and  afternoon  periods  are  added  to- 
gether. Professor  Pieraccini  concludes  that  the  protraction  of 
the  hours  of  labor  raises  the  number  of  accidents  with  each  suc- 
cessive hour,  in  both  the  first  and  second  half  of  the  day.18 

In  Vienna,  Dr.  Leo  Verkauf  has  made  some  investigation  of 
accident-time  in  connection  with  insurance  studies.  His  figures 
refer  to  those  industries  (in  Austria)  in  which  a  short  recess, 
sometimes  of  thirty  minutes,  is  given  at  10  A.M.  and  at  4  P.M.19 
They  show  an  increase  in  the  number  of  accidents  for  the  first 
three  hours  of  the  forenoon  and  of  the  afternoon  periods.  With- 
out some  sort  of  comparative  basis  covering  the  same  industries, 
the  effects  of  the  recess  are  difficult  to  determine. 

Many  conditions  in  Europe  are  different  from  those  in  the 
United  States.  Yet  the  fact  that  European  investigations  are 
uniformly  emphatic  in  the  assertion  that  the  danger  of  accident 
increases  with  continued  work  is  most  significant  for  the  Ameri- 
can situation.  The  fatigue  effects  of  the  great  and  feverish  haste 

11  See  Brandeis  and  Goldmark,  op.  tit.,  252. 
'» E.  R.  Krejcsi,  op.  tit.,  328. 


EMORY  S.   BOGARDUS 


53 


at  which  things  are  done  in  the  United  States  must  be  added  to 
the  regular  fatigue  effects  of  the  more  deliberate  European 
methods  of  operation. 

Table  XII  gives  the  statistics  to  which  reference  has  been 
made  in  the  preceding  paragraphs.  The  totals  appear  at  the 
bottom  of  the  table.  From  these  figures  it  is  not  possible  to 
make  a  comparison  of  the  number  of  accidents  occurring  in  the 
forenoon  with  those  of  the  afternoon  because  the  Saturday  and 
other  half-holidays  depress  the  afternoon  totals  and  because  the 
forenoon  period  is  frequently  of  greater  length  than  the  after- 
noon period.  No  attempt  has  been  made  to  tabulate  accidents 

TABLE  XII 
SUMMARY  OF  ACCIDENT-HOURS 


Hours 

7  to  8 

8  to  9 

9  to  10 

lotoii 

II  tOI2 

la  to  i 

x  to  a 

a  to  3 

3  to  4 

4  to  5 

5  to  6 

Illinois  

97 
156 

163 
380 
818 

25 
232 

794 

747 
500 

9 
ii 

ISO 
244 

208 

538 
1,072 
30 
305 

815 

1,146 
454 
19 

12 

193 
427 

251 
653 
1,332 
2O 
340 

1,069 

1,421 
586 

18 
16 

246 

486 

242 

573 
1,137 
57 
478 

i,598 

i,857 
835 
27 
20 

257 
376 

121 
226 
765 
63 
292 

1,59° 

1,623 
675 
46 

34 

49 
94 

67 
233 
368 

50 
587 

738 
74 
23 
5 

ill 
247 

141 
439 
943 
18 
132 

745 

982 
136 
ii 

9 

156 
407 

165 
634 
1,054 
40 
310 

1,037 

1,408 
403 

18 
14 

227 

435 

203 
590 
1,199 

45 
42i 

1,243 

1,986 

787 

22 
26 

260 
446 

147 
412 

899 
105 
513 

1,178 

2,016 

504 
24 

29 

145 

277 

92 
159 
353 
118 

254 
1,306 

i,5i8 
568 

24 
20 

Wisconsin  .... 
U.S.  (cotton 
mills) 

Minnesota  
Indiana,  etc.  .  . 
France(foriQ03) 
France  (for  1  904) 
Germany  (for 
1887)  

Germany  (for 
1801) 

Belgium 

England  

Denmark  
Total 

3,732 

4,993 

6,326 

7,566 

7,o68 

2,289 

3,914 

5,646 

7,184 

6,533 

4,834 

according  to  the  days  of  the  week.  Not  only  are  there  insuf- 
ficient statistics  to  be  tabulated  in  this  way,  but  the  Sunday 
period  of  supposed  rest  introduces  new  and  complex  factors. 
The  records  for  the  day  following  pay-nights  indicate  that  ab- 
normal factors  have  entered.  As  far  as  accident  records  go 
which  may  be  tabulated  by  the  days  of  the  week,  they  indicate 
a  large  number  of  accidents  on  Monday,  a  much  less  number  on 
Tuesday,  a  gradual  rise  till  the  close  of  the  week,  when  the 
number  of  accidents  on  Monday  is  exceeded.  "In  many  indus- 
tries, notably  the  iron  and  steel,  mining,  textile,  and  railway,  the 


54 


RELATION  OF  FATIGUE  TO  INDUSTRIAL  ACCIDENTS 


number  of  accidents  steadily  increases  from  the  first  or  middle 
of  the  week  and  attains  a  maximum  for  Saturdays."20 


recreation  seems  to  unfit  workmen  for  steady  work  on  Monday, 
"but  fatigue  evidently  plays  a  role  also;  for  even  on  Monday 
the  number  of  accidents  between  9  A.M  and  12  M.  is  larger  than 
between  6  and  9  A.M.,  even  in  proportion  to  the  hours  worked 
in  the  two  periods." 

Table  XII  gives  the  same  general  results  as  Table  V  (Illinois 
statistics)  :  (a)  A  marked  increase  of  accidents  during  the  fore- 
noon period;  (&)  A  decided  fall  after  the  noon  period;  and  (c) 
Another  marked  rise  in  the  afternoon  period.  Accurate  conclu- 
sions regarding  fatigue  effects  must  be  confined  to  those  work- 
hours  when  the  number  actually  at  work  is  uniform  and  when 
the  rapidity  of  work  is  fairly  uniform.  The  hours  of  uniform 
employment  and  of  uniform  rapidity  of  work  as  determined  in 
the  early  portion  of  this  section,  are  from  8  to  11  A.M.  and  from 
i  to  4  P.M.  On  the  basis  of  this  analysis,  Table  XIII  has  been 
constructed;  the  figures  have  been  taken  from  Table  XII.  The 
number  of  accidents  for  the  first  hour  of  the  three-hour  morning 

TABLE  XIII 
ACCIDENT-HOURS  (FINAL  RESULTS) 


FIRST  HOUR 

SECOND  HOUR 

THIRD  HOUR 

8  to  9  Morning 
x  to  2  Afternoon 

9  to  10  Morning 
2  to  3  Afternoon 

10  to  ii  Morning 
3  to  4  Afternoon 

Illinois 

261 

340 

473 

^Visconsin                            .  . 

4QI 

834 

O2I 

U  S  Cotton  Mills. 

•74.0 

416 

44  c 

Tvlinnesota. 

O77 

1,287 

I,l6^ 

Indiana 

2,OI< 

2,386 

2,336 

France  (1003) 

48 

60 

IO2 

France  (1004) 

A27 

6<o 

600 

Germany  (1887) 

t.c6o 

2,106 

2,841 

Germany  (1891) 

2,128 

2,820 

3,843 

Belgium 

(TQO 

080 

1,622 

England 

•JQ 

36 

49 

Denmark 

21 

3O 

46 

Italy 

206 

258 

324 

Total  

9,117 

12,230 

15,064 

'  Bureau  of  Labor  Statistics  (New  York),  XVII,  786. 


EMORY   S.   BOGARDUS  55 

period  of  uniform  employment  and  rapidity  has  been  added  to 
the  number  of  accidents  for  the  first  hour  of  the  afternoon  period 
of  uniform  employment  and  rapidity,  and  so  on.  The  more  or 
less  regular  increase  in  the  number  of  accidents,  hour  by  hour, 
from  9,113  to  12,230  and  from  12,230  to  15,064,  indicates  quite 
definitely  the  results  of  fatigue  in  terms  of  actual  accidents— 
inasmuch  as  extraneous  elements  have  been  largely  accounted 
for  and  not  included  in  these  figures. 

Table  XIII  serves  as  a  basis  for  the  following  conclusion: 
Continuous  work,  other  things  being  equal,  is  accompanied,  hour 
by  hour,  by  an  increasing  number  of  accidents.  Table  XIII  adds 
weight  to  the  statement  of  the  law  of  fatigue  given  at  the  close 
of  Section  III ;  the  increasing  muscular  inaccuracy  which  accom- 
panies uninterrupted  work  results  in  increasing  danger  of  acci- 
dent. Table  XIII  is  offered  in  support  of  the  thesis  of  this 
investigation,  that  fatigue  is  a  cause  of  industrial  accidents. 

In  the  following  section  an  attempt  will  be  made  to  answer 
the  question,  Has  fatigue  attracted  attention  to  itself  to  the 
extent  that  it  has  been  indicted  as  a  cause  of  accidents  by  men 
of  judicial  and  conservative  mind? 

VI.    JUDICIAL  FINDINGS  AND  DECISIONS 

The  accident  statistics  presented  in  the  preceding  section  were 
related  mainly  to  the  development  of  fatigue  and  to  the  increase 
of  accidents  during  the  regular  ten-hour  day.  The  figures  for 
accidents  occurring  during  overtime  work  are  very  inade- 
quate. Light  is  thrown  on  this  point  from  two  important 
sources :  (a)  the  reports  of  the  Interstate  Commerce  Commission, 
and  (&)  the  decisions  of  the  courts.  Although  the  material  used 
in  this  chapter  and  gleaned  from  these  two  sources  is  largely 
incidental  to  the  main  function  of  these  sources,  it  is  for  that 
reason  of  special  value  for  this  investigation.  The  overtime 
accident  cases  cited  in  this  section  are  not  intended  to  show  the 
relative  danger  of  working  "overtime,"  since  there  is  no  ade- 
quate basis  of  comparison.  The  accident  cases  cited  here  are 
those  apparently  due  to  fatigue  of  overwork  and  per  se  are 
offered  as  additional  evidence  in  defense  of  the  thesis  that  fatigue 


56  RELATION  OF  FATIGUE   TO  INDUSTRIAL  ACCIDENTS 

is  a  cause  of  accidents.  No  attempt  has  been  made  here  to  offer 
an  exhaustive  list  of  such  cases.  The  purpose  at  this  point  is 
to  cite  cases  which  will  establish  the  fact,  not  the  quantitative 
extent,  of  fatigue  resulting  from  working  overtime  as  a  cause 
of  accidents. 

For  several  years  past  the  Interstate  Commerce  Commission 
has  concerned  itself  with  a  study  of  railway  accidents;  its  find- 
ings are  published  quarterly.  An  excerpt  germane  to  this  inves- 
tigation follows: 

In  nearly  or  quite  every  bulletin  that  has  been  issued,  it  has  been  neces- 
sary to  record  one  or  more  collisions  due  to  the  mistakes  or  negligence  of 
men  who  have  been  on  duty  so  many  hours  as  to  raise  the  supposition,  if  not 
the  presumption,  that  they  had  become  drowsy,  if  they  had  not  actually 
fallen  asleep;  and  cases  in  which  enginemen  are  definitely  reported  as  being 
asleep  on  duty  are  common.1 

Table  XIV  presents  a  list  of  fifty- four  railway  accidents  com- 
piled from  the  reports  of  the  Interstate  Commerce  Commission. 
In  these  cases,  the  person  or  persons  responsible  for  the  accident 
had  been  on  duty  periods  of  time  varying  from  eleven  hours  and 
nineteen  minutes  to  thirty-nine  hours  and  twenty-five  minutes 
without  intermission  (except  where  noted).2  In  respect  to  the 
accidents  tabulated,  the  Interstate  Commerce  Commission  either 
states  or  directly  implies  that  "the  men  at  fault  had  been  on  duty 
an  excessive  number  of  hours/'3  The  implication  is  clear  that  the 
fatigue  of  overtime  work  was  the  chief  cause  of  these  accidents 
involving  loss  of  life  and  property.  The  facts  upon  which  Table 
XIV  is  based  are  submitted  as  proof  from  an  angle  different 
from  that  of  the  preceding  chapters  that  fatigue  is  a  cause  of  acci- 
dents. Typical  illustrations  of  what  happened  directly  previous 
to  the  occurrence  of  the  given  accidents  are  given : 

Accident  No.  8  (Table  XIV).  Flagman,  who  had  been  ordered  to  hold 
one  of  the  trains,  went  into  caboose  to  get  red  light;  sat  down  to  warm  him- 
self and  dry  his  clothes;  fell  asleep;  had  been  on  duty  sixteen  and  a  half 
hours. 

1  Interstate  Commerce  Commission,  Report,  No.  18,  10. 

'  The  size  of  Table  XTV  is  such  that  limitations  of  space  do  not  permit  its  publication. 
Its  contents,  however,  are  indicated  here. 
3  See  Footnote  i. 


EMORY  S.   BOGARDUS  57 

Accident  No.  30.  Due  to  forgetfulness  on  the  part  of  an  engineman  21 
years  old  who  had  been  on  duty  thirty-nine  hours  and  twenty-five  minutes. 

Accident  No.  34.  Operator  fell  asleep  and  failed  to  deliver  meeting 
order;  on  duty  twenty-four  hours. 

Accident  No.  38.  Engineman  fell  asleep  and  slept  two  minutes;  had 
been  on  duty  twenty-one  hours. 

Accident  No.  32.  (Forty-two  killed  and  injured.)  Operator  turned 

east-bound  passenger  train  on  wrong  delivery  track He  had  been  on 

duty  twenty  hours  and  fifty  minutes. 

Accident  No.  40.  Engineman  fell  asleep  and  passed  automatic  block 
signal  set  against  him;  also  passed  flagman;  had  been  on  duty  seventeen 
hours. 

Accident  No.  41.  Engineman  (killed)  disregarded  flag;  had  been  on 
duty  twenty-eight  hours. 

Accident  No.  46.  (Fifty-six  killed  and  injured.)  Misplaced  switch  at 
meeting  point.  Brakeman  had  been  on  duty  twenty  hours  and  forty  minutes. 

Accident  No.  53.  (Eight  killed  and  injured.)  The  conductor  and  flag- 
man of  the  freight  had  been  on  duty  sixteen  hours  and  fifty  minutes.  The 
freight  was  delayed  ....  the  flagman  was  left  at  "D"  to  stop  the  north- 
bound train After  remaining  at  this  station  about  seven  hours  (the 

flagman)  was  sitting  on  the  steps  of  a  caboose  of  a  freight  train  standing  on 
the  side  track,  with  the  lantern  on  one  of  the  lower  steps  of  the  caboose 
between  his  feet.  While  so  sitting  he  fell  asleep  and  was  not  roused  until  the 
north-bound  train  came  along  and  passed  him  (and  ran  into  the  delayed 
freight). 

Table  XIV  includes  fifty- four  collisions  and  derailments  in 
which  the  total  number  of  killed  and  injured  was  five  hundred 
and  forty-one  persons;  the  total  damage  to  engines,  cars, 
and  roadbed  was  $512,453.  When  the  Interstate  Commerce 
Commission  gives  as  the  chief  cause  in  each  of  these  instances  the 
fact  that  the  men  at  fault  had  been  on  duty  an  excessive  number 
of  hours,  and  when  the  circumstances  preceding  the  given  acci- 
dents are  considered,  the  proof  is  strong  that  the  fatigue  of  over- 
work was  beyond  doubt  the  causal  factor.  Table  XIV  presents 
fifty-four  concrete,  important  cases  in  support  of  the  proposition 
that  fatigue  is  a  cause  of  accidents. 

Further  testimony  in  defense  of  the  thesis  of  this  treatise  has 
been  obtained  from  decisions  of  the  courts — this  is  presented  in 
the  paragraphs  which  follow.  Seven  cases  will  be  cited  here  in 
which  the  courts  have  decided  that  fatigue  was  a  cause  of  the 
given  accidents. 


58  RELATION  OF  FATIGUE  TO   INDUSTRIAL  ACCIDENTS 

(a)  In  the  case  of  Pennsylvania  v.  McCaffrey,  the  Supreme 
Court  of  the  State  of  Indiana  held : 

Unless  it  be  that  a  master  has  a  right  to  require  a  servant  to  stand  at 
his  post  of  duty  without  food  or  rest  for  nineteen  hours  every  day,  Sundays 
included,  and  that  such  conduct  is  not  a  breach  of  duty  to  the  public  as  well 
as  to  its  other  servants,  it  follows  that  the  appellant  (the  railway  company) 
in  this  case  has  not  performed  its  duty  towards  decedent  without  which  it  is 
liable  if  this  negligence  was  the  proximate  cause  of  his  accident.  That  it 
was,  it  is  clear.  The  law  of  nature  is  inexorable  in  its  demands.  The  crav- 
ings of  hunger  must  be  appeased.  The  laws  of  humanity  declare  that  every 
man  fit  to  be  a  member  of  a  train  crew  must  have  three  meals,  some  rest, 
and  eight  hours  sleep  a  day.  The  appellee  well  says:  "Deprived  of  these 
requisites  of  intelligent  life,  a  soldier  becomes  a  coward;  a  workingman  a 
drone."  Any  being  would  lose  his  strength  if  worked  a  few  months  by  the 
time  schedule  provided  for  this  crew.  Every  statute  and  employers'  rule  is 
made  in  the  presence  of,  and  subject  to  the  laws  of  nature.  Hunger,  thirst, 
and  sleep  are  imperative;  and  when  a  schedule  is  made  of  nineteen  con- 
secutive hours  of  service  on  a  train,  and  no  provision  is  made  by  the  company 
for  their  supply  of  food,  it  is  understood  that  the  employees  must,  of  neces- 
sity, at  times  during  the  service,  leave  their  places  to  get  their  meals.  So 
that  when  the  engineer  and  conductor  left  the  train,  after  thirteen  hours' 
service,  on  the  day  of  the  accident,  to  get  their  suppers  it  was  in  obedience 
to  this  law  of  nature — an  over-ruling  necessity,  and  was  not,  therefore, 
negligence  on  their  part.  They  were  not  deserters,  and  their  conduct  cannot 
be  characterized  as  offending  habits.4 

(&)  In  the  case  of  Galveston,  H.  &  S.A.  Ry.  Co.  v.  Broivn 
et  a/.,  the  Court  of  Civic  Appeals  of  Texas  said  : 

In  determining  the  question  of  Brown's  negligence  in  going  to  sleep  on 
his  engine,  the  jury  could  consider  a  fact  in  evidence,  viz.,  that  he  had  been 
working  for  appellant  for  the  five  days  and  nights  preceding  this  accident, 
and  was  overworked  to  such  an  extent  that  sleep  was  unavoidable.  We  think 
that  when  appellant  so  overworks  one  of  its  employees  that  he  cannot  be 
expected  to  stay  awake,  it  ought  not  to  be  allowed  to  say  that  he  was  negli- 
gent in  going  to  sleep,  in  a  question  affecting  the  observance  of  its  rules.8 

(c)  The  Supreme  Court  of  the  State  of  Indiana  has  handed 
down  a  decision  of  special  importance  in  the  case  of  the  Republic 
Iron  &  Steel  Co.  v.  Ohlet.  Excerpts  from  this  decision  are  given 
herewith. 

At  the  time  the  plaintiff  sustained  the  injury  alleged,  he  had  been  work- 
ing continuously,  at  the  instance  and  request  of  the  defendant,  in  the  said 
factory,  for  a  period  of  forty-eight  hours,  without  any  sleep;  and  when  he 
was  ordered  by  said  foreman  to  hold  the  rod,  by  reason  of  his  continuous 

4  38  N.E.  Reporter,  67.  s  59  S.E.  Reporter,  930. 


EMORY   S.   BOGARDUS  59 

work,  without  sleep,  he  did  not  realize  or  appreciate  the  danger  to  which  he 
was  being  subjected It  is  disclosed  that  after  he  had  worked  continu- 
ously some  thirty-six  hours  in  turning  the  rod,  he  informed  Kelly,  the  fore- 
man, that  he  did  not  believe  he  could  endure  the  labor  any  longer;  but  the 
latter  informed  him  that  he  must  continue  at  work  until  the  rod  was 
finished.  It  is  not  reasonable  to  assert  that  a  man  who  has  labored  continu- 
ously for  a  period  of  forty-eight  hours  without  sleep,  or  for  even  a  much 
shorter  time,  is  in  his  normal  condition,  or  that  he  under  the  circumstances 
can  properly  exercise  all  of  the  faculties  or  senses  with  which  he  is  endowed. 
....  A  human  being  deprived  of  sleep  for  the  period  which  appellee  was 
becomes  dull  in  intellect  and  apprehension,  and  necessarily  must  be  more  or 

less  unmindful  of  his  surroundings The  jury  had  the  right  at  least  to 

consider  this  feature  of  the  case,  as  bearing  upon  the  question  whether,  under 
all  of  the  circumstances,  appellee  apprehended  and  appreciated  the  danger 
to  which  he  was  subjected.9 

(d)  In  the  case  of  Pelin  v.  New  York  Centr.  and  H.R.R.  Co., 
the  Supreme  Court  of  New  York,  Appellate  Division,  Fourth 
Department,  reversed  the  trial  court's  decision  in  favor  of  the 
defendant  and  held  that  there  was  sufficient  evidence  to  warrant 
the  jury  in  finding  that  the  injuries  were  due  to  exhaustion  of 
certain  servants  of  the  corporation,  owing  to  their  having  been 
on  duty  twenty- four  consecutive  hours  (in  violation  of  the 
statute).  The  court  also  held  that,  although  those  directing  the 
movements  of  a  train-crew  might  reasonably  have  anticipated 
that  the  run  on  which  the  crew  was  engaged  would  not  last 
twenty- four  consecutive  hours,  the  conditions  of  the  business  of 
the  road  having  been  such  that  the  run  could  not  be  completed  in 
less  than  such  time,  and  an  injury  having  resulted  from  the  ex- 
haustion of  the  crew  owing  to  the  hours  of  work,  the  corporation 
was  liable.  Says  the  court: 

The  statute  is  for  protection  of  employees  liable  to  be  injured  by  the 
carelessness  or  oversight  of  co-employees,  caused  by  exhaustion  induced  by 

long-continued  application  to  work A  railroad  company  with  a  crew 

out  on  a  train  for  more  than  twenty- four  hours  may  elect  to  have  the  trip 
completed  by  the  same  crew.  If  so  it  runs  the  risk  of  liability  for  any  in- 
juries sustained  by  any  of  its  co-employees,  and  which  is  the  proximate  cause 

of  exhaustion  or  inattention  caused  by  such  working  overtime The 

jury  had  a  right  to  say  that  the  fact  that  the  flagman  was  asleep  was  dug  to 
over- exhaustion  by  reason  of  his  protracted  employment,  and  that  the  col- 
lision might  not  have  occurred  had  he  been  in  his  normal  wakeful  condition.* 

*  68  N.E.  Reporter,  901.  *N.Y.  Supp.,  No.  92,  468. 


60  RELATION  OF  FATIGUE   TO   INDUSTRIAL  ACCIDENTS 

(e)  The  case  of  the  Great  Northern  Railway  v.  Couture,  who 
was  injured  while  engaged  as  a  brakeman,  is  directly  to  the  point. 
"The  decision  in  the  reported  case  is  a  novel  one,  and  there  are 
but  few  decisions  upon  the  liability  of  a  master  for  injuries 
caused  by  compelling  him  to  work  an  excessive  number  of 
hours."8  The  court  says : 

A  master  who  keeps  his  servant  continuously  at  work  for  an  undue  number 
of  hours  is  liable  in  damages  for  an  injury  which  the  servant  sustains  in  the 
ordinary  discharge  of  his  duty,  in  consequence  of  his  inability,  from  fatigue 
and  exhaustion,  to  use  the  requisite  skill  and  care.  [The  company  was  held 
liable]  not  upon  alleged  grounds  of  having  used  a  defective  system  of  coupling, 
nor  for  an  excessive  rate  of  speed  in  bringing  the  cars  together,  but  for  keeping 
the  young  man  at  work  for  an  unreasonable  length  of  time  without  sleep. 
....  It  could  not  be  otherwise  than  that  his  bodily  strength  was  at  that  time 
exhausted  and  that  his  mental  faculties  must  have  been  rendered  dull  and  his 

power  of  observation  greatly  weakened The  learned  judge  was  right 

in  holding  the  present  appellants  responsible  ....  in  the  application  of  the 
well-known  principle  that  the  employer's  care  for  his  workmen  must  be  pro- 
portional to  the  risk  of  the  occupation  in  which  he  engages  them.  To  exact 
the  extra-hazardous  risk  of  coupling  the  cars  in  this  instance  required  a  degree 
of  supervision  and  care  on  the  part  of  the  railway  company's  officials,  which 
they  greatly  neglected,  in  compelling  Couture  to  perform  that  work  at  three 
o'clock  in  the  morning,  after  a  service  of  forty-eight  hours,  interrupted  only 
by  two  breaks,  one  of  six  and  one  of  two  hours.  We  have  no  hesitation  in 
adopting  the  learned  trial-judge's  conclusion  in  this  respect,  and  we  believe 
this  considerant  of  his  judgment  was  sufficiently  warranted  by  the  terms  of 
the  plaintiff's  declaration.8 

(/)  In  affirming  the  decision  of  a  lower  court  in  favor  of 
L.  W.  Reed,  administrator,  in  the  case  of  Reed  v.  Southern  Rail- 
way Co.,  the  court  states : 

The  testimony  tended  to  show  that  Reed  had  mistaken  the  time  by  reason 
of  the  fact  that  his  watch  had  run  down ;  but  it  likewise  tended  to  show  that 
this  was  caused  by  the  defendant  in  requiring  or  permitting  Reed  to  operate 
his  engine  for  forty-two  consecutive  hours  immediately  preceding  the  col- 
lision, without  rest,  and  for  twenty-seven  or  twenty-eight  hours  without 
anything  to  eat.  This  was  evidence  of  negligence  [on  the  part  of  the  South- 
ern Railway  Co.].10 

(g)  E.  D.  McCrary,  a  flagman  in  the  employ  of  the  Southern 
Railway  Company,  while  lying  on  the  outside  of  the  tracks 

1  7  Amer.  and  Eng.  Annotated  Cases,  190.  » Ibid.  I0  55  S.E.  Reporter,  218. 


EMORY  S.   BOGARDUS  6 1 

(August  17,  1906)  near  Sheldon,  S.C.,  presumably  asleep,  with 
his  shoulders  between  the  cross-ties  and  his  head  or  a  part  of  it  on 
the  rail,  was  killed  by  a  passing  freight.  In  the  trial  in  the  circuit 
court,  the  Southern  Railway  Company  was  charged  with  care- 
less negligence 

in  requiring  and  permitting  the  said  E.  D.  McCrary  to  act  as  flagman  upon 
said  train,  and  to  go  out  as  flagman  on  the  trip  upon  which  he  was  killed, 
when  the  said  company  through  its  agents  in  service,  knew  or  could  have 
known  that  the  said  E.  D.  McCrary  was  in  such  physical  condition,  owing  to 
the  want  of  sleep  and  rest  as  to  render  him  unfit  to  perform  the  duties  of 
flagman,  ....  and  in  requiring  the  said  E.  D.  McCrary  to  be  and  remain  in 
the  service  of  the  defendant  with  scarcely  any  sleep  or  rest  for  such  a  length 
of  time  immediately  preceding  his  death  as  was  completely  to  exhaust  his 
physical  and  mental  powers,  as  to  render  him  incapable  of  properly  guarding 
himself,  and  the  train  upon  which  he  was  flagging,  against  the  dangers  inci- 
dent to  the  operation  of  trains. 

The  defendants  denied  the  allegation  of  negligence  and  wilfulness  and 
interposed  the  defenses  of  contributory  negligence  and  assumption  of  risk." 

The  jury  rendered  a  verdict  in  favor  of  the  plaintiff  for 
$9>5oo,  and  the  defendant  appealed.  On  June  25,  1909,  the 
Supreme  Court  of  South  Carolina  affirmed  the  judgment  of  the 
circuit  court. 

In  the  seven  cases  cited,  the  courts  have  decided  that  the  re- 
spective accidents  were  due  (a)  not  to  negligence,  but  in  obe- 
dience to  a  law  of  nature,  i.e.,  in  part  to  the  demands  of  fatigue; 
(b)  to  the  fact  that  the  injured  was  overworked  to  such  an  extent 
that  sleep,  the  result  of  overfatigue,  was  unavoidable;  (c)  to  the 
fact  that  the  injured  because  of  fatigue  had  become  dull  in  appre- 
hension and  unmindful  of  his  surroundings;  (d)  to  overex- 
haustion  by  reason  of  protracted  employment;  (e)  as  a  conse- 
quence of  the  inability  of  the  injured  from  fatigue  and 
exhaustion  to  use  the  requisite  skill  and  care;  (/)  to  the  fact  that 
the  fatal  mistake  of  the  injured  was  caused  by  the  fatigue  of 
overwork;  (g)  to  the  exhaustion  of  the  physical  and  mental 
powers  of  the  deceased. 

The  fact  that  fatigue  has  attracted  attention  to  itself  as  a 
cause  of  accidents  to  the  extent  that  such  a  conservative  body 
as  the  judiciary  will  thus  indict  it,  is  noteworthy.  The  seven 

"  65  S.E.  Reporter,  3. 


62  RELATION  OF  FATIGUE   TO   INDUSTRIAL  ACCIDENTS 

cases  which  have  been  summarized  in  the  preceding  paragraphs 
are  not  presented  because  of  any  legal  points  involved  or  for  any 
reasons  other  than  as  a  sevenfold  argument  in  support  of  the 
thesis  that  fatigue  is  a  cause  of  accidents. 

In  the  following  chapter,  all  the  evidence  thus  far  obtained — 
chemical,  physiological,  neural,  psychological,  industrial  (as 
such),  experimental,  statistical,  legal — will  be  brought  together 
and  offered  as  a  unified  whole  in  defense  of  the  thesis  of  this 
investigation.  The  facts  thus  collated  will  be  used  as  a  basis 
for  what  appears  to  the  writer  to  be  the  one  best  method  of  re- 
form and  of  overcoming  fatigue  as  a  cause  of  industrial  acci- 
dents. 

VII.    CONCLUSIONS 

In  this  study  it  has  been  found  (Section  II)  that  continued 
work  is  accompanied  by  the  using  up  of  energy-giving  material 
of  the  muscles  and  nerves  and  by  the  production  and  accumula- 
tion of  toxic  fatigue  substances.  As  a  result  of  these  processes, 
muscles  respond  less  and  less  accurately  and  the  central  nervous 
system  becomes  less  and  less  efficient  in  its  methods  of  control. 
At  a  certain  point  in  the  katabolic  processes  of  the  working  mus- 
cle, inhibitory  impulses  are  sent  in  to  the  cortical  centers  over 
the  afferent  nerves.  These  appear  in  consciousness  in  the  form 
of  sensations  of  effort,  of  strain,  of  fatigue  which  constitute 
warnings  and  which  demand  a  change  in  the  working  mechanism. 
At  the  same  time,  the  working  muscle  gradually  becomes  weaker, 
owing  to  the  using  up  of  its  energy-giving  material,  and  less 
responsive,  owing  to  the  paralyzing  effect  of  the  accumulating 
toxic  substances.  If  the  given  activity  is  continued  long  enough 
or  if  continued  for  a  shorter  time  with  a  high  degree  of  unre- 
laxed  tension,  the  cortical  centers  submit  to  katabolic  processes 
and  become  less  accurate  in  controlling  peripheral  movements. 
The  combined  phases  of  the  fatigue  process  result  in  muscular 
inaccuracy  extending  from  the  immeasurably  small  blockings 
of  the  finely  adjusted  musculature  on  to  the  failure  to  make  the 
grossest  muscular  contractions. 

But  the  nervous  system  is  so  constructed  that  on  occasion  it 
can  call  out  reserve  strengths  and  for  short,  irregular  periods  of 


EMORY  S.   BOGARDUS  63 

time  ward  off  disastrous  fatigue  effects.  Thus  the  progressive 
loss  of  muscular  control  accompanying  work  is  marked  by  irregu- 
larly appearing  spurts  and  depressions.  Upon  these  facts  the 
law  of  fatigue  is  based  which  is  so  generally  a  fundamental  ex- 
planation of  the  cause  of  accidents.  Because  knowledge  of  this 
law  appears  to  be  essential  to  a  thorough  understanding  of  in- 
dustrial accidents,  it  is  restated  here:  Uninterrupted  work  is 
accompanied  by  muscular  inaccuracy  which  increases  irregularly 
and  at  a  rate  dependent  on  the  rate  of  activity  and  on  the  relative 
difficulty  of  the  given  work  for  the  given  individual. 

Section  III  set  forth  the  fact  that  the  increasing  muscular 
inaccuracy  which  accompanies  work  is  greatly  accelerated  by  the 
conditions  peculiar  to  industrial  conditions — by  the  monotonous 
and  speeded-up  operations,  by  the  mental  strain  which  comes 
from  trying  to  attend  to  simple  operations  maintained  at  a  ter- 
rific rate.  When  these  conditions  must  be  met  for  excessive 
hours  without  adequate  rest  periods,  they  lead  to  failure  to  make 
even  the  grossest  co-ordinations — to  sleep  and  exhaustion.  Since 
a  large  proportion,  especially  of  non- fatal  injuries,  occur  in  con- 
nection with  dangerous  machinery  where  a  muscular  inaccuracy 
of  an  inch  or  of  a  fraction  of  an  inch  results  in  mutilation  of 
the  operative,  the  facts  thus  far  reviewed  may  be  summarized 
in  the  statement  that  uninterrupted  work  is  accompanied  by  in- 
creasing muscular  inaccuracy,  which  in  turn  results  in  increasing 
chances  of  accident. 

In  the  series  of  controlled  experiments  (Section  IV),  it  was 
definitely  shown  that  even  in  a  short  period  of  work  involving 
monotony,  speed,  mental  strain,  where  a  high  degree  of  voli- 
tional power  might  be  called  out  for  the  full  time,  practically 
two-thirds  of  the  muscular  inaccuracies  occurred  in  the  last  half 
of  the  period.  When  the  rate  of  work  in  these  experiments  was 
increased  and  as  long  as  the  rate  was  a  "speeded-up"  one  for  the 
given  individual,  the  number  of  errors  was  and  remained  ab- 
normally increased;  moreover,  the  abnormal  increase  developed 
quite  generally  in  the  second  half  of  the  work  periods. 

The  results  of  these  experiments  show  that  fatigue  is  an  ever- 
constant  factor  in  continued  work,  that  the  appearance  of  this 


64  RELATION  OF  FATIGUE   TO  INDUSTRIAL  ACCIDENTS 

constant  factor  in  the  foreground  during  a  given  work  period 
depends  in  part  on  the  rapidity  of  work.  These  results  illu- 
minate the  proposition  that  uninterrupted  work  is  accompanied 
by  muscular  inaccuracy  which  increases  at  a  rate  dependent  on 
the  rate  of  activity.  When  given  an  industrial  interpretation, 
these  results  indicate  that  continued  work  in  the  dangerous  trades 
is  accompanied  during  each  of  the  succeeding  work  periods  by 
increasing  chances  of  accident  and  at  a  rate  correlative  with  the 
speed  of  work. 

The  statistics  of  the  hours  when  accidents  occur  (Section  V) 
show  complex  results.  As  a  basis  for  conclusions  work  periods 
were  taken  when  the  factors  of  "warming  up"  and  "final  spurt" 
are  eliminated,  when  a  uniform  number  of  people  are  at  work, 
and  when  a  fairly  uniform  degree  of  speed  was  maintained. 
Statistics  for  such  work  periods  show  a  regularly  and  pronounced 
rise  in  the  number  of  accidents  from  hour  to  hour.  If  extrane- 
ous factors  are  not  included  statistics  of  accident-hours  indi- 
cate clearly  that  fatigue  is  a  cause  of  industrial  accidents.  These 
statistics  make  possible  a  description  of  typical  succession  of 
events:  (a)  the  development  of  fatigue  due  to  monotonous, 
speeded-up  work  under  a  high  pressure  of  mental  strain  main- 
tained for  long  hours  at  a  time;  (b)  the  development  of  mus- 
cular inaccuracies  due  to  this  increasing  fatigue;  (c)  increasing 
numbers  of  accidents  due  immediately  to  this  increasing  loss  of 
muscular  accuracy. 

The  case  against  fatigue  of  overwork  is  becoming  so  clear 
that  it  is  receiving  attention  in  the  findings  of  such  a  group  of 
men  as  compose  the  Interstate  Commerce  Commission  and  in  the 
decisions  of  the  conservative  courts.  Legal  authorities  have  in- 
dicted fatigue  as  a  cause  of  accidents  and  the  related  decisions 
have  been  presented  (Section  VI)  in  further  defense  of  the  thesis 
of  this  investigation. 

In  the  preceding  paragraphs  the  facts  have  been  summarized 
upon  which  the  thesis  is  maintained  that  fatigue  is  a  cause  of 
industrial  accidents.  A  word  of  explanation  is  needed  at  this 
point.  The  accidents  which  formerly  were  bulked  together  and 
attributed  to  carelessness  now  receive  a  more  careful  explanation. 


EMORY  S.   BOGARDUS  65 

Dr.  Emil  Roth  says  that  that  which  is  often  ascribed  to  the  care- 
lessness ("auf  das  Konto  des  Leichtsinns  und  der  Nachlassig- 
keit")  of  the  worker  is  in  reality  the  result  of  oncoming  fatigue.1 
Professor  Adams  states  that  this  carelessness  which  has  been 
alleged  as  a  cause  of  accidents  "we  are  now  beginning  to  realize 
is  often  due  to  the  mere  stress  and  strain  under  which  modern  fac- 
tory operatives  work."2  Carelessness  is  not  an  ultimate  cause,  says 
Elizabeth  Butler  in  her  study  of  Women  and  the  Trades,  but  a 
resultant  from  any  one  of  a  multitude  of  things,  one  of  which 
is  the  haste  and  disregard  of  personal  risk  resulting  almost  in- 
evitably from  a  piece-work  system.3 

Crystal  Eastman,  who  has  made  a  study  of  the  causes  of  those 
fatal  accidents  which  are  commonly  spoken  t>f  as  due  to  the 
"carelessness  of  the  man  injured,"  says  that  instead  of  95  per 
cent,  only  32  per  cent  of  the  fatal  accidents  can  be  laid  in  a 
measure  to  the  responsibility  of  the  victims ;  that  of  this  32  per 
cent,  1 1  per  cent  is  not  due  to  carelessness,  strictly  speaking,  but 
to  ignorance,  youth,  and  physical  weakness;  that  in  the  case  of 
the  remaining  21  per  cent  of  the  fatalities  actually  due  to  care- 
lessness, some  of  the  men  were  heedless,  some  inattentive,  and/ 
some  reckless.4 

For  the  heedless  ones  no  defense  is  made.  For  the  inattentive  we  main- 
tain that  human  powers  of  attention,  universally  limited,  are  in  their  case 
further  limited  by  the  conditions  under  which  the  work  is  done — long  hours, 
heat,  noise,  intense  speed.  For  the  reckless  ones,  we  maintain  that  natural 
inclination  is  in  their  case  encouraged  and  inevitably  increased  by  an  occu- 
pation involving  constant  risk;  recklessness  is  part  of  the  trade.  Not  all 
accidents  due  to  inattention  and  recklessness  can  be  thus  defended;  but 
speaking  generally  these  two  kinds  of  carelessness  cannot  fairly  be  called 
faults  of  the  workman. 

So-called  carelessness  may  be  explained  by  the  fact  that  the 
fatigued  workman  is  unable  to  give  as  close  attention  to  safety 
appliances  and  machine  guards  as  a  normally  resistant  workman 
can  give.  In  their  laundry  investigation,  Clark  and  Wyatt  found 

1  Emil  Roth,  14.  Intern.  Kong.,  etc.,  IV,  290. 

a  Adams  and  Summer,  Labor  Problems  (Macmillan,  1908),  483. 

3  Eliz.  B.  Butler,  Women  and  the  Trades  (Charities  Pub.  Com.,  1909),  108. 

4  Crystal  Eastman,  Work  Accidents  and  the  Law  (Charities  Pub.  Com.,  1910),  95. 


66  RELATION  OF  FATIGUE   TO   INDUSTRIAL  ACCIDENTS 

that  "each  burn  is  due  to  carelessness,"  but  that  if  the  girls  were 
to  be  careful,  they  would  have  to  focus  their  minds  on  self- 
protection,  instead  of  on  the  proper  accomplishment  of  their 
tasks,  and  would  also  have  to  work  at  a  lower  rate  of  speed.5 
Hence  it  is  becoming  evident  that  accidents  which  have  been 
hastily  and  unscientifically  classed  as  due  to  "negligence"  or  to 
"carelessness"  are  in  reality  due  to  the  inexorable  demands  of 
the  overworked  human  organism. 

In  concluding  this  summary,  it  may  be  added  that  as  soon 
as  it  becomes  evident  that  fatigue  is  a  cause  of  accidents  and  as 
soon  as  the  way  in  which  fatigue  causes  accidents  becomes  clear, 
definite  methods  of  prevention  must  be  determined  upon  and  put 
into  operation.  /Society  cannot  afford  tQ,_allow  its  industrial 
members  to  submit  themselves  unduly  to  the  law  of  fatigue  un- 
dlerlying  accidents  or  to  be  coercedTby  external  ~c^Sditions"  in  a 
sjmilar__fashipnT'  Society  cannot  afford  to  permit  wage-earners" 
because  of  the  fatigue  effects  of  long  hours  of  monotonous, 
speeded-up  toil  to  be  destroyed  or  even  to  be  removed  temporarily 
or  permanently  as  means  of  support  to  large  families  (and  the 
support  of  these  families  thus  to  be  thrown  upon  the  public). 

The  deaths  and  disablements  due  to  fatigue  represent  a  need- 
less waste  to  society.  Louis  M.  Greeley  says  that  every  day  the 
enormous  waste  to  society  from  industrial  accidents  becomes 
clearer,  that  the  burden  imposed  upon  public  charity  becomes 
heavier,  and  that  the  conviction  becomes  stronger  that  our  present 
inaction  in  these  matters  must  give  place  to  intelligent  action  in 
order  that  these  great  evils  be  lessened.6 

At  this  point,  the  question  logically  follows:  What  can  be 
done  to  reduce  the  fatigue  which  causes  accidents?7  The 
answer  must  be  psychological  and  economic.  Make  it  over- 
whelmingly to  the  financial  advantage  of  employers  to  reduce  to 
the  narrowest  limits  the  number  of  accidents  that  befall  their 

s  Clark  and  Wyatt,  "Women  Laundry  Workers  in  New  York,"  McClure's,  XXXVI, 
404. 

'L.  M.  Greeley,  "Changing  Attitude  of  the  Courts  toward  Social  Legislation,"  Survey, 
XXIV,  778. 

7  It  will  be  clear  that  the  defense  of  the  thesis  of  this  investigation  does  not  in  itself  call 
for  an  elaborate  discussion  of  measures  for  prevention.  Consequently,  the  suggestions  made 
here  will  be  presented  only  in  outline  form. 


EMORY  S.   BOGARDUS  67 

employees.8  The  chief  way  to  prevent  fatigue-accidents  effec- 
tively is  to  make  the  lives  and  limbs  of  his  employees  as  impor- 
tant to  an  employer  as  the  output.9  The  all-important  measure 
in  minimizing  fatigue-accidents  appears  to  be  compulsory  acci- 
dent-insurance (constitutionality  granted,  of  course).10  This 
method  of  prevention  works  better  than  any  other  in  Germany, 
and  is  described  briefly  by  Professor  Henderson : 

The  German  industrial-insurance  law  requires  the  employers  to  pay  one- 
third  of  the  cost  of  sickness-insurance,  and  all  the  premiums  for  accident- 
insurance;  the  sickness-insurance  fund  cares  for  the  disabled  workman  for 
thirteen  weeks,  after  which  the  employers'  fund  pays  for  further  support 
during  disablement  due  to  accident.  Naturally,  it  is  seen  to  be  to  the  interest 
of  all  parties  to  reduce  the  number  of  accidents  to  the  lowest  possible  level 
by  taking  all  precautions  suggested  by  experience.  If  a  workingman  is 
careless  he  may  be  fined  and  thus  disciplined  to  observance  of  the  regula- 
tions made  for  his  benefit.  If  a  certain  factory  shows  a  high  rate  of  injury 
to  employees,  its  assessment  is  correspondingly  raised  by  the  executive  com- 
mittee. The  accident-insurance  law  works  automatically  to  reduce  accidents.11 

(a)  It  is  safe  to  say  that  when  it  becomes  financially  ad- 
vantageous to  employers  to  minimize  danger  of  accident  to 
employees  they  will  replace  monotonous  and  speeded-up  hand- 
operations  as  far  as  possible  by  automatic  processes.  Piece-work 
in  connection  with  dangerous  machines  will  be  supplanted  by 
time-work.  Miss  Anderson,  chief  lady  inspector  in  England, 
says  that  by  cutting  down  piece-work  the  danger  of  accidents 
will  be  lessened.  In  laundries  more  than  one  manageress  has  been 
able  to  minimize  the  risk  of  accident  by  insisting  on  payment  by 
time,  not  by  piece.12  It  follows  from  the  law  of  fatigue  (Sec- 

•H.  R.  Seager,  Industrial  Insurance  (Macmillan,  1910),  28. 

'  Crystal  Eastman,  op.  tit.,  106. 

"A  problem  for  investigation  arises  at  this  point:  What  effect  has  compulsory  accident- 
insurance  in  Germany  had  upon  the  number  of  accidents  per  year  per  thousand  ?  Adequate 
data  are  not  at  hand  whereby  a  definite  answer  can  be  given.  The  situation  is  exceedingly 
complex  and  many  factors  would  have  to  be  given  consideration,  some  of  which  may  be  indi- 
cated, (i)  Year  after  year  employees  are  speeded  up  in  order  to  secure  an  increasing  output — 
and  a  higher  accident  rate  would  naturally  result  from  higher  rates  of  speed.  (2)  During  the 
industrial  development  of  a  country,  untrained  and  inexperienced  workmen  are  constantly 
being  added  to  the  force — a  fact  which  would  tend  to  increase  the  accident  rate.  (3)  Stricter 
control  is  exercised  now  than  twenty-five  or  even  ten  year?-,  ago  in  reporting  accidents.  Many 
other  factors  might  be  mentioned. 

11  C.  R.  Henderson,  "Wood-Workers  and  Their  Dangers,"  World  To-Day,  XXXVI,  976. 

"  A.  M.  Anderson,  Sess.  Papers  (House  of  Lords,  1004),  LIX,  201. 


68  RELATION  OF  FATIGUE  TO  INDUSTRIAL  ACCIDENTS 

tion  II),  and  from  the  results  of  the  experiments  (Section  IV), 
that  a  reduction  in  speed  would  mean  a  reduction  in  chances  of 
accident. 

But  in  many  industries  a  reduction  in  speed  is  hardly  prac- 
ticable— competition  and  economic  demands  are  too  strong.  To 
reduce  speed  would  seem  a  retrogression  in  industry.  Where  it 
is  impossible  to  substitute  automatic  machines,  the  employer 
whose  employees  have  been  made  as  valuable  to  him  as  his  out- 
put (by  compulsory  accident-insurance)  will  lessen  the  dangers 
of  speed  by  shortening  hours  of  work.13 

(b)  Under  compulsory  accident- insurance  laws  the  employer 
would  lessen  the  danger  of  accidents  by  making  hours  of  continu- 
ous work  commensurate  with  the  intensity  and  danger  of  the 
work.    Crystal  Eastman  says  that  shorter  hours — an  eight-hour 
day  for  all  railroaders — is  about  the  most  important  thing  to 
reduce  the  number  of  accidents.14    In  regard  to  the  employees 
in  the  dangerous  wire-mills,  Miss  Eastman  says  that  one  way  to 
lessen  danger  of  accident  will  be  "to  reduce  the  hours  and  shorten 
the  shift."15 

Greater  intensity  of  work  necessitates  longer  periods  of  relaxation.  If 
the  strain  of  the  work  cannot  be  lessened,  the  duration  must  be.  Think  of 
the  crane  man  (in  the  steel-mill)  upon  whose  alertness  and  care  depend  the 
lives  of  several  others.  His  is  a  hot,  unpleasant,  lonely  job.  There  is  no 
one  to  spell  him.  He  cannot  get  down  from  his  cab  for  any  reason.  And 
he  works  twelve  hours  every  day  in  the  year  except  Christmas  and  the 
Fourth  of  July.  No  steel  company  can  maintain  that  it  has  done  everything 
to  prevent  accidents  until  it  has  reduced  the  working  hours  of  men  in  such 
responsible  positions." 

(c)  Men  and  women  must  not  be  allowed  to  work  at  speeded 
and  dangerous  machines  according  to  personal  ambition  but  ac- 
cording to  the  physical  ability  of  the  given  individuals.    This  norm 
will  be  attained  not  by  the  methods  of  the  ordinary  factory  in- 
spector nor  even  by  medical  factory  inspection,  but  ultimately  by 
examinations  including  tests  possibly  similar  to  those  described  in 
Section  IV  in  which  each  individual  receives  expert  attention. 
The  physically  unfit  for  the  more  dangerous  forms  of  work  must 
be  weeded  out  by  expert  tests;  they  must  not  be  allowed  as  now 

"  Crystal  Eastman,  op.  cit.,  74.  '« Ibid.,  33.  **Ibid.t  86.  "Ibid.,  74. 


EMORY  S.   BOGARDUS  69 

to  assume  the  more  dangerous  forms  of  work  from  economic 
motives  and  be  eliminated  by  the  painful  and  costly  method  of 
accident;  for  here  as  elsewhere  the  law  of  the  survival  of  the 
fittest  holds.  The  physical  ability  (and  mental  alertness)  of  the 
worker  and  the  hours  of  work  must  be  proportional  to  the  fa- 
tiguing character  and  danger  of  the  work. 

(d)  Compulsory  accident-insurance  so  regulated  that  the  em- 
ployee must  contribute  a  certain  percentage  of  the  fund  from 
which  compensations  are  paid  will  enlist  the  strong  forces  of 
labor  itself,  from  individual  laborers  as  such,  to  the  powerful 
labor  unions,  in  a  more  successful  fight  against  fatigue  and  other 
causes  of  accidents.  When  it  is  made  to  the  financial  advantage 
of  both  employee  and  employer  to  reduce  accidents,  safety 
appliances,  for  example,  will  be  not  only  installed,  but  actually 
used.  Employers  and  employees  must  use  various  methods  of 
instructing  new  and  uninitiated  workers  as  to  the  subtle  dangers 
of  fatigue.  "Ignorance  permits  accidents  which  might  be  pre- 
vented."17 The  potential  force  of  the  labor  union  under  rational 
control,  as  a  means  of  securing  education  of  employees  in  in- 
dustrial hygiene,  of  securing  shorter  hours  and  more  adequate 
rest  periods,  etc.,  would  be  aroused  to  activity  if  it  were  made 
to  the  financial  advantage  of  the  union  to  do  so.  The  union, 
made  up  of  the  workers  themselves,  is  always  present  to  observe 
violations,  which  cannot  be  the  case,  for  instance,  with  factory 
inspectors. 

While  a  discussion  of  methods  for  prevention  of  fatigue  as  a 
cause  of  accidents  does  not  properly  belong  here,  it  is  maintained 
that  a  method  worthy  of  consideration  is  compulsory  accident- 
insurance — granted  the  constitutionality  of  such  a  procedure,  of 
course.  In  other  words,  it  is  contended  that  in  the  prevention  of 
fatigue  as  a  cause  of  accidents,  the  will  of  the  employer  is  pre- 
eminently important,  and  the  will  of  the  employees  expressed 
through  labor  unions  under  rational  control  is  of  next  importance. 

17  C.  R.  Henderson,  "Social  Cost  of  Accident,  Ignorance  and  Exhaustion,"  Pamphlet 
No.  72,  National  Child  Labor  Commission  (New  York,  1908). 


-   • 


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